The P1002 trouble code is a manufacturer-specific powertrain code. Its exact definition depends entirely on the vehicle application, ranging from ignition timer faults to fuel pump module issues.
Because it is manufacturer-specific, the exact application must be verified. The code identifies a detected condition, and testing is required to identify the root cause.
Quick Navigation
Key Takeaways
- P1002 is a manufacturer-specific powertrain code with definitions varying by automaker.
- On Chrysler, Dodge, and Jeep applications, it indicates an ignition key off timer performance fault.
- On GM applications, it points to a fuel pump driver control module system voltage performance issue.
- On Ford applications, it indicates an ignition switch interruption detected during engine operation.
- Proper diagnosis requires verifying the exact factory definition and testing the relevant system circuits.
P1002 Code Description and Implications
The P1002 code is a manufacturer-specific powertrain definition. Because it is not a generic SAE code, its exact meaning depends entirely on the vehicle application.
Chrysler, Dodge, and Jeep applications: On these vehicles, P1002 indicates an ignition key off timer performance fault. The Transmission Control Module relies on the ignition off time stored in the Cabin Compartment Node to enable diagnostic tests.
GM applications: On Cadillac, GMC, and Chevrolet vehicles, P1002 indicates a fuel pump driver control module system voltage performance issue. The powertrain control module monitors the voltage supplied to the fuel pump driver module and sets this error code if a fault is detected.
Ford applications: On certain Ford vehicles, P1002 indicates that the powertrain control module detected an ignition power interruption during engine operation.
BMW applications: On some BMW models, P1002 indicates a Valvetronic limp home request low input fault within the variable valve lift system.
Common Causes of the P1002 Code
Electrical faults, module communication errors, and component failures are the primary triggers, though the specific causes vary by manufacturer.
For Chrysler, Dodge, and Jeep ignition timer systems: The issue may stem from a faulty ignition switch, an open or short in the ignition switch circuit, poor electrical connections, or a communication failure between modules.
For GM fuel pump systems: The fault is caused by a failed fuel pump driver control module, damaged wiring between the module and the powertrain control module, or a poor ground connection for the fuel pump circuit.
For Ford ignition circuits: The issue is typically caused by a failing ignition switch, damaged wiring in the ignition run/start circuit, or a poor connection at the powertrain control module.
Symptoms Associated With P1002
Symptoms vary drastically based on which system has detected the fault.
Chrysler, Dodge, and Jeep applications: The primary symptom is an illuminated Check Engine Light. You may also experience issues with transmission operation or failed emissions readiness monitors due to the inability to run key-off diagnostic tests.
GM applications: You may experience a no-start condition, extended cranking, or severe engine stalling due to the fuel pump driver module failing to supply the correct voltage to the fuel pump.
Ford applications: The engine may experience intermittent resets, unstable operation, or stalling if the ignition power circuit drops out while the engine is running.
Diagnosing the P1002 Trouble Code
Accurate diagnosis requires confirming the exact factory definition for your specific make and model before proceeding.
Chrysler, Dodge, and Jeep diagnosis: Use a scan tool to monitor the ignition off timer data and check the communication network between modules. Inspect the ignition switch wiring harness for opens, shorts, or high resistance.
GM diagnosis: Test the voltage supply and ground circuits at the fuel pump driver control module. Verify the module’s output voltage to the fuel pump and check the signal circuit between the module and the powertrain control module.
Ford diagnosis: Monitor the ignition switch voltage data while the engine is running to detect intermittent dropouts. Inspect the ignition switch connector and wiring for loose pins or chafed insulation.
Repairing the P1002 Issue
Repairs must address the specific root cause identified during testing for your vehicle’s system.
Wiring and connector repairs: If an open, short, or corroded connector is found, repair the wiring or replace the connector pigtail using appropriate materials.
Component replacement: If the wiring is intact but the circuit remains faulty, the ignition switch, fuel pump driver control module, or Cabin Compartment Node may require replacement.
Cost Considerations for P1002 Repairs
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Replacing an ignition switch is generally a straightforward repair with moderate parts and labor costs. Replacing a fuel pump driver control module may require additional programming and fuel system access, increasing the overall cost.
Prevention Strategies for Future Occurrences
While internal module failures cannot always be predicted, you can protect the external circuits from common damage.
Inspecting exposed wiring and connectors near the steering column or fuel tank can help identify developing damage, chafing, or moisture intrusion before it causes a circuit fault.
Troubleshooting Tips and Best Practices
Do not assume a control module requires replacement just because a P1002 code is present. A pinched wire or a loose connector will produce the exact same circuit fault reading.
Always check the relevant fuses and power supplies first. A blown fuse or a poor ground will prevent the module from operating and trigger the code.
Check for Technical Service Bulletins for your specific vehicle. Manufacturers frequently release updated module part numbers or revised wiring harnesses to address chronic circuit faults.
More OBD-II Codes
| P0775 | P0776 | P0780 | P0785 |
| P1000 | P1001 | P1003 | P1004 |
| P1005 | P1008 | P1009 | P1010 |
| P0601 | P0602 | P0603 | P0604 |
| P0605 | P0606 | P0607 | P0620 |
| P0621 | P0622 | P0627 | P0628 |
Frequently Asked Questions
Is P1002 a generic or manufacturer-specific code?
No. P1002 is a manufacturer-specific powertrain code. Its definition varies by brand, indicating an ignition timer fault on Chrysler vehicles, a fuel pump module issue on GM, or an ignition interruption on Ford.
Can I drive my car with a P1002 code?
If the code relates to an ignition timer, the vehicle may drive normally but fail emissions tests. If it affects the fuel pump module or ignition switch, the engine may stall unexpectedly, making driving unsafe.
Will disconnecting the battery clear the P1002 code?
Disconnecting the battery may temporarily erase the code, but it will not repair a physical wiring fault or failed module. The code will return once the monitor runs again.
Can a bad ground cause a P1002 code?
Yes. On GM applications, a poor ground connection at the fuel pump driver control module can cause system voltage performance issues, triggering the code. Cleaning the ground may resolve the fault.
Does P1002 always mean the ignition switch is bad?
No. The code identifies a detected circuit condition. This is frequently caused by damaged wiring, a poor connector, or a communication fault. The switch should only be replaced after electrical testing confirms failure.
What Should You Do About the P1002 Code?
Confirm the exact factory definition for your vehicle, then follow the applicable manufacturer diagnostic procedure. Because P1002 is manufacturer-specific, the diagnostic path for an ignition timer differs from a fuel pump module or ignition switch circuit.
Inspect the relevant system and components, including wiring harnesses, modules, and connectors. Repair any confirmed faults, or replace the relevant system components only after testing verifies the failure.
