What Are GM OBD2 Fault Codes And How To Diagnose Them?

Gm Obd2 Fault Codes are standardized diagnostic trouble codes used in General Motors vehicles to identify malfunctions. MERCEDES-DIAGNOSTIC-TOOL.EDU.VN offers comprehensive resources to help you understand these codes and effectively diagnose issues. Understanding these codes, along with related diagnostic procedures, empowers both vehicle owners and technicians to troubleshoot automotive problems effectively, leading to accurate repairs and improved vehicle performance, with efficient solutions for car diagnostics and troubleshooting.

1. Understanding GM OBD2 Fault Codes

What are GM OBD2 fault codes and why are they important for vehicle diagnostics?

GM OBD2 fault codes are standardized codes that the vehicle’s computer system, or Engine Control Module (ECM), uses to identify specific problems within the car. These codes are crucial because they provide a starting point for diagnosing issues, saving time and money on unnecessary repairs. According to the Environmental Protection Agency (EPA), all cars sold in the United States since 1996 are required to have an OBD2 system.

1.1 What is OBD2?

OBD2, or On-Board Diagnostics II, is a standardized system that monitors various components of a vehicle, including the engine, transmission, and emissions systems. The system is designed to detect malfunctions and alert the driver through the check engine light on the dashboard. When a problem is detected, the ECM stores a corresponding fault code.

1.2 Structure of a GM OBD2 Fault Code

GM OBD2 fault codes follow a specific format. Each code consists of five characters: one letter followed by four numbers. The letter indicates the system where the fault occurred:

• P: Powertrain (engine, transmission)
• B: Body (airbags, central locking)
• C: Chassis (ABS, suspension)
• U: Network (communication bus)

The first number indicates whether the code is generic (0) or manufacturer-specific (1). The remaining three numbers specify the exact fault. For instance, P0300 indicates a random or multiple cylinder misfire, while P0101 refers to a Mass Air Flow (MAF) sensor performance issue.

1.3 Importance of Understanding Fault Codes

Understanding GM OBD2 fault codes is essential for several reasons:

• Accurate Diagnosis: Fault codes help pinpoint the source of the problem, reducing guesswork.
• Cost Savings: By identifying the issue early, you can prevent more extensive and costly damage.
• Informed Decisions: Knowing the fault code allows you to discuss the problem intelligently with a mechanic.
• Preventative Maintenance: Addressing minor issues promptly can improve the vehicle’s overall reliability and longevity.

1.4 Tools for Reading OBD2 Fault Codes

To read GM OBD2 fault codes, you will need an OBD2 scanner. These scanners range from basic handheld devices to more advanced tools that can provide live data and perform diagnostic tests. Some popular options include:

• Basic OBD2 Scanners: Affordable and easy to use, these scanners read and clear fault codes.
• Mid-Range Scanners: Offer additional features such as live data streaming and freeze frame data.
• Professional Scanners: Provide advanced diagnostics, including bi-directional control and module programming.

1.5 Locating the OBD2 Port

The OBD2 port is typically located under the dashboard on the driver’s side. It is a 16-pin connector that provides access to the vehicle’s computer system. Consult your vehicle’s manual for the exact location if you are unsure.

1.6 Common GM OBD2 Fault Codes

Here are some of the most common GM OBD2 fault codes and their potential causes:

• P0101: Mass Air Flow (MAF) Sensor Circuit Range/Performance Problem. Possible causes include a dirty or faulty MAF sensor, vacuum leaks, or wiring issues.
• P0171/P0174: System Too Lean Bank 1/Bank 2. This could be due to vacuum leaks, a faulty oxygen sensor, or a dirty fuel filter.
• P0300: Random/Multiple Cylinder Misfire Detected. Potential causes include faulty spark plugs, ignition coils, fuel injectors, or vacuum leaks.
• P0420: Catalyst System Efficiency Below Threshold Bank 1. This often indicates a failing catalytic converter or issues with the oxygen sensors.
• P0442: Evaporative Emission Control System Leak Detected (Small Leak). Common causes include a loose or damaged gas cap, faulty purge valve, or cracked EVAP hoses.

1.7 Resources for Further Learning

To deepen your understanding of GM OBD2 fault codes, consider the following resources:

• Vehicle Repair Manuals: Provide detailed information on specific vehicle models and their diagnostic procedures.
• Online Forums: Engage with other car enthusiasts and professionals to share knowledge and experiences.
• Online Databases: Websites like OBD-Codes.com offer comprehensive information on fault codes and their potential solutions.
• Professional Training Courses: Consider taking a course on automotive diagnostics to gain hands-on experience and in-depth knowledge.

By understanding the basics of GM OBD2 fault codes and using the right tools and resources, you can diagnose and address vehicle problems more effectively, ensuring optimal performance and longevity.

2. Decoding Specific GM Powertrain Diagnostic Trouble Codes

How do you decode specific GM powertrain diagnostic trouble codes (DTCs)?

Decoding specific GM powertrain diagnostic trouble codes (DTCs) requires a systematic approach. Each code provides unique information about the potential issue within the vehicle’s powertrain system. Understanding the structure, common codes, and diagnostic procedures can streamline the troubleshooting process.

2.1 Understanding the Powertrain System

The powertrain system includes all components that generate power and transfer it to the wheels. Key components include the engine, transmission, driveshaft, axles, and differential. When a fault occurs within this system, the ECM stores a DTC, which can be retrieved using an OBD2 scanner.

2.2 Structure of GM Powertrain DTCs

GM powertrain DTCs follow the standard OBD2 format, beginning with the letter “P” followed by four numbers. The second character indicates whether the code is generic (0) or manufacturer-specific (1). The remaining three digits specify the exact fault.

2.3 Common GM Powertrain DTCs and Their Meanings

Here are some common GM powertrain DTCs and their typical meanings:

• P0101: Mass Air Flow (MAF) Sensor Circuit Range/Performance: Indicates an issue with the MAF sensor, which measures the amount of air entering the engine. Potential causes include a dirty or faulty MAF sensor, vacuum leaks, or wiring problems.
• P0171/P0174: System Too Lean Bank 1/Bank 2: Suggests that the engine is receiving too much air or not enough fuel. Common causes include vacuum leaks, a faulty oxygen sensor, or a clogged fuel filter.
• P0300: Random/Multiple Cylinder Misfire Detected: Indicates that one or more cylinders are not firing properly. Potential causes include faulty spark plugs, ignition coils, fuel injectors, or vacuum leaks.
• P0301-P0308: Cylinder X Misfire Detected: Specifies a misfire in a particular cylinder, where X is the cylinder number (e.g., P0301 indicates a misfire in cylinder 1).
• P0420: Catalyst System Efficiency Below Threshold Bank 1: Suggests that the catalytic converter is not functioning efficiently. This can be due to a failing catalytic converter or issues with the oxygen sensors.
• P0442: Evaporative Emission Control System Leak Detected (Small Leak): Indicates a small leak in the evaporative emission control system. Common causes include a loose or damaged gas cap, faulty purge valve, or cracked EVAP hoses.
• P0700: Transmission Control System Malfunction: Indicates a general issue with the transmission control system. Further diagnosis is typically required to pinpoint the exact problem.

2.4 Detailed Diagnostic Steps

When you encounter a GM powertrain DTC, follow these steps for effective diagnosis:

1. Retrieve the DTC: Use an OBD2 scanner to read the stored fault code from the vehicle’s ECM.
2. Record Freeze Frame Data: Note the freeze frame data, which provides a snapshot of the engine conditions when the fault occurred. This can offer valuable clues about the cause of the problem.
3. Research the DTC: Consult repair manuals, online databases, or professional resources to understand the specific meaning and potential causes of the DTC.
4. Inspect Related Components: Examine the components and systems related to the DTC. Look for obvious signs of damage, such as broken wires, loose connections, or leaking hoses.
5. Perform Diagnostic Tests: Conduct specific tests to verify the functionality of the affected components. For example, you can use a multimeter to check the resistance and voltage of sensors.
6. Clear the DTC and Retest: After making repairs, clear the DTC using the OBD2 scanner and retest the vehicle to ensure the problem has been resolved.

2.5 Advanced Diagnostic Tools

For more complex powertrain issues, consider using advanced diagnostic tools:

• Professional Scan Tools: Offer bi-directional control, allowing you to command specific components to activate and observe their response.
• Multimeters: Essential for testing the electrical circuits and components.
• Smoke Machines: Used to detect vacuum leaks in the intake and exhaust systems.
• Fuel Pressure Testers: Help diagnose fuel delivery problems.

2.6 Case Study: Diagnosing a P0300 Code

Let’s consider a case study to illustrate the diagnostic process. Suppose you retrieve a P0300 code from a GM vehicle, indicating a random/multiple cylinder misfire. Here’s how you might proceed:

1. Verify the Code: Confirm the presence of the P0300 code using an OBD2 scanner.
2. Check for Additional Codes: Look for any other related DTCs, such as specific cylinder misfire codes (P0301-P0308).
3. Inspect Spark Plugs: Remove and inspect the spark plugs for signs of wear, damage, or fouling. Replace any faulty spark plugs.
4. Test Ignition Coils: Use a spark tester or multimeter to check the ignition coils for proper function. Replace any weak or non-functioning coils.
5. Check Fuel Injectors: Inspect the fuel injectors for proper spray pattern and flow. Clean or replace any clogged or malfunctioning injectors.
6. Look for Vacuum Leaks: Use a smoke machine to check for vacuum leaks in the intake manifold and vacuum hoses. Repair any leaks.
7. Perform Compression Test: Conduct a compression test to check for cylinder compression issues. Low compression can indicate valve or piston ring problems.
8. Clear the Code and Retest: After completing the repairs, clear the P0300 code and retest the vehicle to ensure the misfire has been resolved.

2.7 When to Seek Professional Help

While many powertrain issues can be diagnosed and repaired by experienced DIYers, some problems require professional expertise. Consider seeking help from a qualified mechanic if:

• You lack the necessary tools or equipment.
• You are uncomfortable working on certain components.
• The problem is complex or requires specialized knowledge.
• You are unable to resolve the issue after performing basic diagnostic steps.

2.8 Utilizing MERCEDES-DIAGNOSTIC-TOOL.EDU.VN

MERCEDES-DIAGNOSTIC-TOOL.EDU.VN provides valuable resources to assist in decoding GM powertrain DTCs. From detailed code descriptions to step-by-step diagnostic guides, the website offers a wealth of information to help you effectively troubleshoot and repair your vehicle.

By following these guidelines, you can systematically decode GM powertrain DTCs and efficiently diagnose and repair issues within the vehicle’s powertrain system.

3. Comprehensive List of GM Specific Powertrain Diagnostic Trouble Codes

What is a comprehensive list of GM specific powertrain diagnostic trouble codes?

A comprehensive list of GM specific powertrain diagnostic trouble codes is essential for accurate diagnosis and repair. These codes provide detailed information about potential issues within the vehicle’s powertrain system. This section outlines a wide range of GM specific DTCs, offering a valuable reference for technicians and vehicle owners.

3.1 Understanding GM Specific DTCs

GM specific DTCs are manufacturer-defined codes that provide more detailed information than generic OBD2 codes. These codes are particularly useful for diagnosing complex issues within GM vehicles.

3.2 List of GM Specific Powertrain Diagnostic Trouble Codes

Below is a comprehensive list of GM specific powertrain diagnostic trouble codes (P1XXX):

• P1031: HO2S Heater Current Monitor Control Circuit Banks 1 and 2 Sensor 1
• P1032: HO2S Heater Warm Up Control Circuit Banks 1 and 2 Sensor 1
• P1105: Secondary Vacuum Sensor Circuit
• P1106: Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent High Voltage
• P1107: Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent Low Voltage
• P1108: BARO to MAP Sensor Comparison Too High
• P1109: Secondary Port Throttle System
• P1111: Intake Air Temperature (IAT) Sensor Circuit Intermittent High Voltage
• P1112: Intake Air Temperature (IAT) Sensor Circuit Intermittent Low Voltage
• P1113: Intake Resonance Switchover Solenoid Control Circuit
• P1114: Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low Voltage
• P1115: Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage
• P1116: ECT Signal Unstable or Intermittent
• P1117: Engine Coolant Temp. Signal Out-Of-Range Low
• P1118: Engine Coolant Temp. Signal Out-Of-Range High
• P1119: ECT Signal Out-Of-Range With TFT Sensor
• P1120: Throttle Position (TP) Sensor 1 Circuit
• P1121: Throttle Position (TP) Sensor Circuit Intermittent High Voltage
• P1122: Throttle Position (TP) Sensor Circuit Intermittent Low Voltage
• P1125: APP System
• P1130: HO2S Circuit Low Variance Bank 1 Sensor 1
• P1131: HO2S Circuit Low Variance Bank 1 Sensor 2
• P1132: HO2S Circuit Low Variance Bank 2 Sensor 1
• P1133: HO2S Insufficient Switching Bank 1 Sensor 1
• P1134: HO2S Transition Time Ratio Bank 1 Sensor 1
• P1135: HO2S Lean Mean Bank 1 Sensor 1
• P1136: HO2S Rich Mean Bank 1 Sensor 1
• P1137: HO2S Bank 1 Sensor 2 Lean System or Low Voltage
• P1138: HO2S Bank 1 Sensor 2 Rich or High Voltage
• P1139: HO2S Insuff. Switching Bank 1 Sensor 2
• P1140: HO2S Transition Time Ratio Bank 1 Sensor 2
• P1141: HO2S Heater Control Circuit Bank 1 Sensor 2
• P1143: HO2S Bank 1 Sensor 3 Lean System or Low Voltage
• P1144: HO2S Bank 1 Sensor 3 Rich or High Voltage
• P1145: HO2S Cross Counts Bank 1 Sensor 3
• P1153: HO2S Insufficient Switching Bank 2 Sensor 1
• P1154: HO2S Transition Time Ratio Bank 2 Sensor 1
• P1155: HO2S Lean Mean Bank 2 Sensor 1
• P1156: HO2S Rich Mean Bank 2 Sensor 1
• P1157: HO2S Bank 2 Sensor 2 Lean System or Low Voltage
• P1158: HO2S Bank 2 Sensor 2 Rich or High Voltage
• P1159: HO2S Cross Counts Bank 2 Sensor 2
• P1161: HO2S Heater Control Circuit Bank 2 Sensor 2
• P1163: HO2S Bank 2 Sensor 3 Lean System or Low Voltage
• P1164: HO2S Bank 2 Sensor 3 Rich or High Voltage
• P1165: HO2S Cross Counts Bank 2 Sensor 3
• P1170: Bank to Bank Fuel TrimOffset
• P1171: Fuel System Lean During Acceleration
• P1185: Engine Oil Temperature Circuit
• P1186: EOT Circuit Performance
• P1187: EOT Sensor Ckt. Low Voltage
• P1188: EOT Sensor Ckt. High Voltage
• P1189: Engine Oil Pressure (EOP) Switch Circuit
• P1190: Engine Vacuum Leak
• P1191: Intake Air Duct Air Leak
• P1200: Injector Control Circuit
• P1201: (Alt. Fuel) Gas Mass Sensor Circuit Range/Performance
• P1202: (Alt. Fuel) Gas Mass Sensor Circuit Low Frequency
• P1203: (Alt. Fuel) Gas Mass Sensor Circuit High Frequency
• P1211: Mass Air Flow Circuit Intermittent High
• P1212: Mass Air Flow Circuit Intermittent Low
• P1214: Injection Pump Timing Offset
• P1215: Ground Fault Detection Indicated
• P1216: Fuel Solenoid Response Time Too Short
• P1217: Fuel Solenoid Response Time Too Long
• P1218: Injection Pump Calibration Circuit
• P1219: Throttle Position Sensor Reference Voltage
• P1220: Throttle Position (TP) Sensor 2 Circuit
• P1221: Fuel Pump Secondary Circuit Low
• P1222: Injector Control Circuit Intermittent
• P1225: Injector Circuit Cylinder 2 Intermittent
• P1228: Injector Circuit Cylinder 3 Intermittent
• P1231: Injector Circuit Cylinder 4 Intermittent
• P1234: Injector Circuit Cylinder 5 Intermittent
• P1237: Injector Circuit Cylinder 6 Intermittent
• P1240: Injector Circuit Cylinder 7 Intermittent
• P1243: Injector Circuit Cylinder 8 Intermittent
• P1245: Intake Plenum Switchover Valve
• P1250: Early Fuel Evaporation Heater Circuit
• P1257: Supercharger System Overboost
• P1258: Engine Coolant Overtemperature – Protection Mode Active
• P1260: Last Test Failed Failed SCC ENTER:More Info.
• P1270: Accelerator Pedal Position Sensor A/D Converter Error
• P1271: Accelerator Pedal Position (APP) Sensor 1-2 Correlation
• P1272: Accelerator Pedal Position Sensor 2
• P1273: Accelerator Pedal Position Sensor 1
• P1274: Injectors Wired Incorrectly
• P1275: Accelerator Pedal Position (APP) Sensor 1 Circuit
• P1276: Accelerator Pedal Position Sensor 1 Circuit Performance
• P1277: Accelerator Pedal Position Sensor 1 Circuit Low Voltage
• P1278: Accelerator Pedal Position Sensor 1 Circuit High Voltage
• P1280: Accelerator Pedal Position (APP) Sensor 2 Circuit
• P1281: Accelerator Pedal Position Sensor 2 Circuit Performance
• P1282: Accelerator Pedal Position Sensor 2 Circuit Low Voltage
• P1283: Accelerator Pedal Position Sensor 2 Circuit High Voltage
• P1285: Accelerator Pedal Position Sensor 3 Circuit
• P1286: Accelerator Pedal Position Sensor 3 Circuit Performance
• P1287: Accelerator Pedal Position Sensor 3 Circuit Low Voltage
• P1288: Accelerator Pedal Position Sensor 3 Circuit High Voltage
• P1300: Ignitor Circuit DTC
• P1305: Ignition Coil 2 Primary Feedback Circuit
• P1310: Ignition Coil 3 Primary Feedback Circuit
• P1315: Ignition Coil 4 Primary Feedback Circuit
• P1320: IC 4X Reference Circuit Intermittent
• P1321: Electronic Ignition System Fault Line
• P1322: EI System or Ignition Control Extra or Missing
• P1323: IC 24X Reference Circuit Low Frequency
• P1324: Crank RPM Too Low
• P1335: CKP Circuit
• P1336: Crankshaft Position (CKP) System Variation Not Learned
• P1345: Crankshaft Position (CKP)-Camshaft Position (CMP) Correlation
• P1346: Intake Camshaft Position [CMP] Sensor System Performance
• P1350: Ignition Control System
• P1351: Ignition Coil Control Circuit High Voltage
• P1352: IC Output High/Pulse Detected when GND_Cyl. 2
• P1353: IC Output High/Pulse Detected when GND_Cyl. 3
• P1354: IC Output High/Pulse Detected when GND_Cyl. 4
• P1355: IC Output High/Pulse Detected when GND_Cyl. 5
• P1356: IC Output High/Pulse Detected when GND_Cyl. 6
• P1357: IC Output High/Pulse Detected when GND_Cyl. 7
• P1358: IC Output High/Pulse Detected when GND_Cyl. 8
• P1359: Ignition Coil Group 1 Control Circuit
• P1360: Ignition Coil Group 2 Control Circuit
• P1361: Ignition Coil Control Circuit Low Voltage
• P1362: IC Cylinder 2 Not Toggling After Enable
• P1363: IC Cylinder 3 Not Toggling After Enable
• P1364: IC Cylinder 4 Not Toggling After Enable
• P1365: IC Cylinder 5 Not Toggling After Enable
• P1366: IC Cylinder 6 Not Toggling After Enable
• P1367: IC Cylinder 7 Not Toggling After Enable
• P1368: IC Cylinder 8 Not Toggling After Enable
• P1370: IC 4X Reference Circuit Too Many Pulses
• P1371: IC 4X Reference Circuit Too Few Pulses
• P1372: Crankshaft Position (CKP) Sensor A-B Correlation
• P1374: 3X Reference Circuit
• P1375: IC 24X Reference Circuit High Voltage
• P1376: Ignition Ground Circuit
• P1377: IC Cam Pulse To 4X Reference Pulse
• P1380: Misfire Detected – Rough Road Data Not Available
• P1381: Misfire Detected – No Communication with Brake Control Module
• P1390: Wheel Speed Sensor 1 – G – Sensor Circuit
• P1391: Wheel Speed Sensor 1 – G – Sensor Circuit Performance
• P1392: Wheel Speed Sensor 1 – G – Sensor Circuit Low Voltage
• P1393: Wheel Speed Sensor 1 – G – Sensor Circuit High Voltage
• P1394: Wheel Speed Sensor 1 – G – Sensor Circuit Intermittent
• P1395: Wheel Speed Sensor 2 – G – Sensor Circuit
• P1396: Wheel Speed Sensor 2 – G – Sensor Circuit Performance
• P1397: Wheel Speed Sensor 2 – G – Sensor Circuit Low Voltage
• P1398: Wheel Speed Sensor 2 – G – Sensor Circuit High Voltage
• P1399: Wheel Speed Sensor 2 – G – Sensor Circuit Intermittent
• P1403: Exhaust Gas Recirculation System Valve 1
• P1404: Exhaust Gas Recirculation (EGR) Closed Position Performance
• P1405: Exhaust Gas Recirculation System Valve 3
• P1406: EGR Valve Pintle Position Circuit
• P1407: EGR Air Intrusion in Exhaust Supply to EGR Valve
• P1408: Intake Manifold Pressure Sensor Circuit
• P1409: EGR Vacuum System Leak
• P1410: Fuel Tank Pressure System
• P1415: Secondary Air Injection (AIR) System Bank 1
• P1416: Secondary Air Injection (AIR) System Bank 2
• P1418: Secondary Air Injection System Relay A Control Circuit High
• P1420: Intake Air Low Pressure Switch Circuit Low Voltage
• P1421: Intake Air Low Pressure Switch Circuit High Voltage
• P1423: Intake Air High Pressure Switch Circuit High Voltage
• P1431: Fuel Level Sensor 2 Circuit Performance
• P1432: Fuel Level Sensor 2 Circuit Low Voltage
• P1433: Fuel Level Sensor 2 Circuit High Voltage
• P1441: Evaporative Emission (EVAP) System Flow During Non-Purge
• P1442: EVAP Vacuum Sw. High Voltage During Ign. On
• P1450: Barometric Pressure Sensor Circuit
• P1451: Barometric Press. Sensor Performance
• P1460: Cooling Fan Control System
• P1460: Misfire Detected With Low Fuel Level
• P1480: Cooling Fan 1 Control Circuit High
• P1483: Engine Cooling System Performance
• P1500: Starter Signal Circuit
• P1501: Theft Deterrent System
• P1501: Vehicle Speed Sensor Circuit Intermittent
• P1502: Theft Deterrent Fuel Enable Signal Not Received
• P1503: Theft Deterrent Fuel Enable Signal Not Correct
• P1504: Vehicle Speed Output Circuit
• P1508: Idle Speed Low – Idle Air Control (IAC) System Not Responding
• P1509: Idle Speed High – Idle Air Control (IAC) System Not Responding
• P1510: Throttle Control System Performance – Throttle Limitation Active
• P1511: Throttle Control System – Backup System Performance
• P1514: Airflow to TP Sensor Correlation High
• P1515: Electronic Throttle System Throttle Position
• P1516: Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance
• P1517: Electronic Throttle Module
• P1518: Electronic Throttle Module to PCM Communication
• P1519: Throttle Actuator Control (TAC) Module Internal Circuit
• P1520: Transmission Range Switch Circuit
• P1521: Transmission Engaged at High Throttle Angle
• P1522: Park/Neutral to Drive/Reverse at High RPM
• P1523: Throttle Closed Position Performance
• P1524: Throttle Closed Position Performance
• P1525: Throttle Body ServiceRequired
• P1526: Minimum Throttle Position Not Learned
• P1527: Transmission Range to Pressure Switch Correlation
• P1528: Governor
• P1529: Heated Windshield Request Problem
• P1530: Throttle Actuator Control (TAC) Module Internal Circuit
• P1531: A/C Low Side Temperature Sensor Fault
• P1532: A/C Evaporator Temp. Sens. Ckt. Low Voltage
• P1533: A/C Evaporator Temp. Sens. Ckt. High Voltage
• P1534: A/C High Side Temp. Sensor Low Voltage
• P1535: A/C High Side Temperature Sensor Circuit
• P1536: Engine Coolant Overtemperature – Air Conditioning (A/C) Disabled
• P1537: A/C Request Circuit Low Voltage
• P1538: A/C Request Circuit High Voltage
• P1539: A/C Clutch Status Circuit High Voltage
• P1540: Air Conditioning (A/C) Refrigerant Overpressure – Air Conditioning (A/C) Disabled
• P1541: A/C High Side Over Temperature
• P1542: A/C System High Pressure High Temperature
• P1543: A/C System Performance
• P1544: A/C Refrigerant Condition Very Low
• P1545: Air Conditioning (A/C) Clutch Relay Control Circuit
• P1546: A/C Clutch Status Circuit Low Voltage
• P1547: A/C System Performance Degraded
• P1548: A/C Recirculation Circuit
• P1554: Cruise Control Feedback Circuit
• P1555: Electronic Variable Orifice Output
• P1558: Cruise Control Servo Indicates Low
• P1559: Cruise Control Power Management Mode
• P1560: Transaxle Not in Drive – Cruise Control Disabled
• P1561: Cruise Vent Solenoid
• P1562: Cruise Vacuum Solenoid
• P1563: Cruise Vehicle Speed/Set Speed Difference Too High
• P1564: Vehicle Acceleration Too High – Cruise Control Disabled
• P1565: Cruise Servo Position Sensor
• P1566: Engine RPM Too High – Cruise Control Disabled
• P1567: Active Banking Control Active – Cruise Control Disabled
• P1568: Cruise Servo Stroke Greater than Commanded in Cruise
• P1569: Cruise Servo Stroke High While not in Cruise
• P1570: Traction Control Active – Cruise Control Disabled
• P1571: Traction Control Torque Request Circuit
• P1572: ASR Active Circuit Low Too Long
• P1573: PCM/EBTCM Serial Data Circuit
• P1574: Stoplamp Switch Circuit
• P1575: Extended Travel Brake Switch Circuit
• P1576: BBV Sensor Ckt. High Voltage
• P1577: BBV Sensor Ckt. Low Voltage
• P1578: BBV Sensor Ckt. Low Vacuum
• P1579: P/N to D/R at High Throttle Angle – Power Reduction Mode Active
• P1580: Cruise Move Circuit Low Voltage
• P1581: Cruise Move Circuit High Voltage
• P1582: Cruise Direction Circuit Low Voltage
• P1583: Cruise Direction Circuit High Voltage
• P1584: Cruise Control Disabled
• P1585: Cruise Control Inhibit Output Circuit
• P1586: Cruise Control Brake Switch 2 Circuit
• P1587: Cruise Control Clutch Control Circuit Low
• P1588: Cruise Control Clutch Control Circuit High
• P1599: Engine Stall or Near Stall Detected
• P1600: TCM Internal Watchdog Operation
• P1601: Serial Comm. Problem With Device 1
• P1602: Knock Sensor (KS) Module Performance
• P1603: Loss of SDM Serial Data
• P1604: Loss of IPC Serial Data
• P1605: Loss of HVAC Serial Data
• P1606: Serial Communication Problem With Device 6
• P1607: Serial Communication Problem With Device 7
• P1608: Serial Communication Problem With Device 8
• P1609: Loss Of TCS Serial Data
• P1610: Loss of PZM Serial Data
• P1611: Loss of CVRTD Serial Data
• P1612: Loss of IPM Serial Data
• P1613: Loss of DIM Serial Data
• P1614: Loss of RIM Serial Data
• P1615: Loss of VTD Serial Data
• P1617: Engine Oil Level Switch Circuit
• P1619: Engine Oil Life Monitor Reset Circuit
• P1620: Low Coolant Circuit
• P1621: Control Module Long Term Memory Performance
• P1622: Cylinder Select
• P1623: Transmission Temp Pull-Up Resistor
• P1624: Customer Snapshot Requested – Data Available
• P1625: TCM System Reset
• P1626: Theft Deterrent Fuel Enable Signal Not Received
• P1627: A/D Performance
• P1628: ECT Pull-Up Resistor
• P1629: Theft Deterrent System – Cranking Signal
• P1630: Theft Deterrent Learn Mode Active
• P1631: Theft Deterrent Start Enable Signal Not Correct
• P1632: Theft Deterrent Fuel Disable Signal Received
• P1633: Ignition 0 Switch Circuit
• P1634: Ignition 1 Switch Circuit
• P1635: 5 Volt Reference Circuit
• P1636: PCM Stack Overrun
• P1637: Generator L-Terminal Circuit
• P1638: Generator F-Terminal Circuit
• P1639: 5 Volt Reference 2 Circuit
• P1640: Driver