Just like the Oracle of Delphi, your GMC’s onboard computer holds the secrets of its inner workings, waiting to be deciphered. When the “check engine” light illuminates, it’s like receiving a cryptic message from the automotive gods. But fear not, for the GMC OBD-II codes hold the key to deciphering the mystery.
These five-digit codes can pinpoint issues with your vehicle’s powertrain system, from fuel injector circuits to engine misfires. But what do they really mean, and how can you use them to troubleshoot and repair your ride? The answer lies just ahead.
Understanding GMC OBD-II Codes
What exactly do GMC OBD-II codes represent in your vehicle’s self-diagnostic system?
They’re a set of five-digit codes that indicate specific component issues, helping you identify problems with your engine, transmission, and drivetrain accessories.
The first digit of the code tells you if it’s a manufacturer-specific issue (P1, P2, or P3) or a generic one (P0).
P codes deal with the powertrain system, including fuel and air metering, fuel injector circuits, engine misfires, and auxiliary emissions controls.
A faulty Throttle Position Sensor, for instance, can trigger a Diagnostic Trouble Code (DTC) that’ll show up as a P code.
Common Diagnostic Trouble Codes
When you’ve grasped the basics of GMC OBD-II codes, it’s time to explore into the specific fault codes that can help you pinpoint issues in your vehicle.
You’ll likely encounter common diagnostic trouble codes like P1260, indicating a failed self-test that requires immediate attention.
Others, such as P1352, P1353, and P1354, relate to IC Output High/Pulse Detected, signaling a problem with the ignition coil or spark plug.
The P1442 code points to an EVAP vacuum switch high voltage issue, while P2123 corresponds to an Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage problem, affecting the throttle control system.
Additionally, you might see P0073, which is related to the Mass Air Flow Ambient Air Sensor temperature, indicating a possible issue with the engine’s air intake system.
Code Resolution and Community Support
Now that you’ve identified the trouble code, it’s crucial to take the next step and resolve the issue.
Clearing OBD-II codes involves reading the code, clearing it, and monitoring the vehicle’s gauges to guarantee the issue is resolved.
For example, resolving code P2123, Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage, typically requires replacing the Pedal Position (APP) Sensor and throttle position sensor.
In the same way, code P0073, Mass Air Flow Ambient Air Sensor temperature, can be resolved by replacing the MAF sensor.
After correcting the problem, you’ll need to reset the OBD-II system following a specific procedure.
Online forums and community support provide valuable resources for troubleshooting and resolving OBD-II codes, allowing you to share knowledge and expertise with others who’ve faced identical issues.
Most Common GMC OBD-II Trouble Codes
Powertrain (P) Codes
| Code | Description |
|---|---|
| P0420 | Catalytic Converter Efficiency Below Threshold |
| P0300 | Random/Multiple Cylinder Misfire Detected |
| 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 | MAP Sensor Circuit Intermittent High Voltage |
| P1107 | MAP Sensor Circuit Intermittent Low Voltage |
| P1108 | BARO to MAP Sensor Comparison Too High |
| P1260 | Last Test Failed SCC |
| P1270 | Accelerator Pedal Position Sensor A/D Converter Error |
| P1296 | Injector Control Module Circuit Malfunction Bank 2 |
Chassis (C) Codes
| Code | Description |
|---|---|
| C0561 | ABS System Disabled Information Stored |
| P1390 | Wheel Speed Sensor 1 – G – Sensor Circuit |
| P1391 | Wheel Speed Sensor 1 – G – Performance |
| P1392 | Wheel Speed Sensor 1 – G – Low Voltage |
| P1393 | Wheel Speed Sensor 1 – G – High Voltage |
Body (B-Codes)
| Code | Description |
|---|---|
| B0198 | Blower Motor #1 Power Circuit Malfunction |
| B0199 | Blower Motor #1 Power Circuit Range/Performance |
| B0200 | Blower Motor #1 Power Circuit Low |
| B0201 | Blower Motor #1 Power Circuit High |
| B0213 | Blower Motor #2 Power Circuit Malfunction |
| B0214 | Blower Motor #2 Power Circuit Range/Performance |
Communication (U) and System Codes
| Code | Description |
|---|---|
| P1603 | Loss of SDM Serial Data |
| P1604 | Loss of IPC Serial Data |
| P1605 | Loss of HVAC Serial Data |
| P1610 | Loss of PZM Serial Data |
| P1611 | Loss of CVRTD Serial Data |
| P1612 | Loss of IPM Serial Data |
Transmission Codes
| Code | Description |
|---|---|
| P1810 | TFP Valve Position Switch Circuit |
| P1811 | Maximum Adapt and Long Shift |
| P1812 | Transmission Over Temperature Condition |
| P1813 | Torque Control |
| P1814 | Torque Converter Overstressed |
| P1815 | Transmission Range Switch – Start In Wrong Range |
Engine Management
| Code | Description |
|---|---|
| P0261 | Cylinder 1 Injector Circuit Low |
| P0262 | Cylinder 1 Injector Circuit High |
| P0263 | Cylinder 1 Contribution/Balance Fault |
| P0264 | Cylinder 2 Injector Circuit Low |
| P0265 | Cylinder 2 Injector Circuit High |
