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. Reading and Clearing Diagnostic Trouble Codes
1. Turn the ignition switch to ON (II).
2. Check for Pending or Confirmed DTCs with the HDS.
Are any Pending or Confirmed 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 24.
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 24.
5. Check for dirt or debris in the air cleaner element.
Is it dirty?
YES - Replace the air cleaner element or remove the debris, Service and Repair then go to step 24.
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 pulse plate. CKP Pulse Plate Replacement
Is the CKP sensor and/or the CKP pulse plate damaged?
YES - Replace the CKP sensor CKP Sensor Replacement and/or the CKP pulse 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 24.
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. While holding the engine speed at 2,500 rpm for 30 seconds, check the MAF SENSOR in the DATA LIST with the HDS.
Is there about 5.7-8.3 gm/s?
YES - Go to step 15.
NO - Replace the MAF sensor/IAT sensor, Service and Repair then go to step 24.
15. Turn the ignition switch to LOCK (0).
16. Drain the coolant. Service and Repair
17. Remove ECT sensor 1, ECT Sensor 1 Replacement and ECT sensor 2. ECT Sensor 2 Replacement
18. Allow the sensors to cool to the ambient temperature.
19. Note the ambient temperature.
20. Connect ECT sensor 1 and ECT sensor 2 to their 2P connectors, but do not install them.
21. Turn the ignition switch to ON (II).
22. Note the value of ECT SENSOR 1 and ECT SENSOR 2 quickly in the DATA LIST with the HDS.
23. Compare the value of ECT SENSOR 1 to the ambient temperature, and the value of ECT SENSOR 2 to 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 24.
NO - Check and repair any problems with the following items. Repair or replace them if needed, then go to step 24. If all of the items are OK, go to step 31.
- Engine compression and cylinder leakdown
- VTEC system
- Engine oil
- A/C system
- Power steering
24. Turn the ignition switch to ON (II).
25. Reset the ECM with the HDS.
26. Do the ECM idle learn procedure. ECM/PCM Idle Learn Procedure
27. Let the engine cool until the value of ECT SENSOR 1 is 122 °F (50 °C) or less.
28. Start the engine, and let it idle for 10 seconds or more.
29. Check for Pending or Confirmed 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 30.
30. 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 Pending or Confirmed DTCs were indicated in step 29, 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 27.
31. Update the ECM if it does not have the latest software, ECM/PCM Update or substitute a known-good ECM. Reading and Clearing Diagnostic Trouble Codes
32. Do the ECM idle learn procedure. ECM/PCM Idle Learn Procedure
33. Let the engine cool until the value of ECT SENSOR 1 is 122 °F (50 °C) or less.
34. Start the engine, and let it idle for 10 seconds or more.
35. Check for Pending or Confirmed 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, Reading and Clearing Diagnostic Trouble Codes then go to step 33. If the ECM was substituted, go to step 1.
NO - Go to step 36.
36. 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 Pending or Confirmed DTCs were indicated in step 35, 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, Reading and Clearing Diagnostic Trouble Codes then go to step 33. 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 33.