DTC Troubleshooting
DTC Troubleshooting: P050B
DTC P050B: Cold Start Ignition Timing Control System Performance Problem
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Initial Inspection and Diagnostic Overview
1. Turn the ignition switch to ON (II).
2. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs other than P050B indicated?
YES - Go to the indicated DTC's troubleshooting.
NO - Go to step 3.
3. Check for poor connections or a blockage at the intake air duct.
Is it OK?
YES - Go to step 4.
NO - Reconnect or repair the intake air duct, then go to step 25.
4. Check for damage to the air cleaner housing.
Is it OK?
YES - Go to step 5.
NO - Replace the air cleaner housing, Service and Repair then go to step 25.
5. Check for dirt or debris in the air cleaner element.
Is it dirty?
YES - Replace the air cleaner element or remove the debris, Testing and Inspection then go to step 25.
NO - Go to step 6.
6. Let the engine cool until the value of ECT SENSOR 1 is 122 °F (50 °C) or less.
7. Clear the DTC with the HDS.
8. Start the engine, and let it idle for 10 seconds or more.
9. Monitor the OBD STATUS for DTC P050B in the DTCs MENU with the HDS.
Does the screen indicate FAILED?
YES - Go to step 10.
NO - If the screen indicates PASSED, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the throttle body, the MAF sensor/IAT sensor, and the ECM. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 6.
10. Check the ignition timing. Testing and Inspection
Is the ignition timing OK?
YES - Go to step 12.
NO - Go to step 11.
11. Check for damage at the CKP sensor CKP Sensor Replacement and the CKP sensor pulser plate. CKP Pulse Plate Replacement
Is the CKP sensor and/or the CKP sensor pulser plate damaged?
YES - Replace the CKP sensor CKP Sensor Replacement and/or the CKP sensor pulser plate, CKP Pulse Plate Replacement then go to step 6.
NO - Go to step 31.
12. Do the ETCS TEST in the INSPECTION MENU with the HDS.
Is the THROTTLE ACTUATOR CONTROL VALVE normal?
YES - Go to step 13.
NO - Replace the throttle body, Removal and Replacement then go to step 25.
13. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.
14. Monitor the ENGINE SPEED in the DATA LIST with the HDS, and hold the engine speed at 2,500 rpm for at least 30 seconds.
15. While holding the engine speed at 2,500 rpm, check the MAF SENSOR in the DATA LIST with the HDS.
Is there about 5.7-8.3 gm/s?
YES - Go to step 16.
NO - Replace the MAF sensor/IAT sensor, Service and Repair then go to step 25.
16. Turn the ignition switch to LOCK (0).
17. Drain the coolant. Service and Repair
18. Remove ECT sensor 1, ECT Sensor 1 Replacement and ECT sensor 2. ECT Sensor 2 Replacement
19. Allow the sensors to cool to ambient temperature.
20. Note the ambient temperature.
21. Connect ECT sensor 1 and ECT sensor 2 to their 2P connectors, but do not install them.
22. Turn the ignition switch to ON (II).
23. Note the value of ECT SENSOR 1 and ECT SENSOR 2 quickly in the DATA LIST with the HDS.
24. Compare the value of ECT SENSOR 1 and the ambient temperature, and the value of ECT SENSOR 2 and the ambient temperature individually.
Does either sensor differ more than 5.4 °F (3 °C) from the ambient temperature?
YES - Replace the sensor that differed more than 5.4 °F (3 °C) from the ambient temperature, then go to step 25.
NO - Check and repair any problems with the following items. Repair or replace them if needed, then go to step 25. If all the items are OK, go to step 32.
- Engine compression and cylinder leakdown
- VTEC system
- Engine oil
- A/C system
- Power steering
25. Turn the ignition switch to ON (II).
26. Reset the ECM with the HDS.
27. Do the ECM idle learn procedure. ECM Idle Learn Procedure
28. Let the engine cool until the value of ECT SENSOR 1 is 122 °F (50 °C) or less.
29. Start the engine, and let it idle for 10 seconds or more.
30. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P050B indicated?
YES - Check for poor connections or loose terminals at the CKP sensor, the throttle body, the MAF sensor/IAT sensor, ECT sensor 1, ECT sensor 2, and the ECM, then go to step 1.
NO - Go to step 31.
31. Monitor the OBD STATUS for DTC P050B in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 30, go to the indicated DTC's troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the CKP sensor, the throttle body, the MAF sensor/IAT sensor, ECT sensor 1, ECT sensor 2, and the ECM, then go to step 1. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 28.
32. Update the ECM if it does not have the latest software, ECM Update or substitute a known-good ECM. Initial Inspection and Diagnostic Overview
33. Do the ECM idle learn procedure. ECM Idle Learn Procedure
34. Let the engine cool until the value of ECT SENSOR 1 is 122 °F (50 °C) or less.
35. Start the engine, and let it idle for 10 seconds or more.
36. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P050B indicated?
YES - Check for poor connections or loose terminals at the CKP sensor, the throttle body, the MAF sensor/IAT sensor, ECT sensor 1, ECT sensor 2, and the ECM. If the ECM was updated, substitute a known-good ECM, Initial Inspection and Diagnostic Overview then go to step 34. If the ECM was substituted, go to step 1.
NO - Go to step 37.
37. Monitor the OBD STATUS for DTC P050B in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. Service and Repair If any other Temporary DTCs or DTCs were indicated in step 36, go to the indicated DTC's troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the CKP sensor, the throttle body, the MAF sensor/IAT sensor, ECT sensor 1, ECT sensor 2, and the ECM. If the ECM was updated, substitute a known-good ECM, Initial Inspection and Diagnostic Overview then go to step 34. If the ECM was substituted, go to step 1. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 34.