DTC P050B: Cold Start Ignition Timing Control System Performance Problem
- Turn the ignition switch to ON (II).
- 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.
- Check for poor connections or a blockage at the intake air duct.
Is it OK?
YES -Go to step 4.
NO -Correct the problem, then reconnect the intake air duct, then go to step 21.
- Check for damage at the air cleaner housing.
Is it OK?
YES -Go to step 5.
NO -Replace the air cleaner housing (see AIR CLEANER REMOVAL/INSTALLATION ), then go to step 21.
- Check for dirt or debris in the air cleaner element.
Is it dirty?
YES -Replace the air cleaner element or remove the debris (see AIR CLEANER REMOVAL/INSTALLATION ), then go to step 21.
NO -Go to step 6.
- Let the engine cool until the value of ECT SENSOR 1 is 122°F (50°C) or less.
- Clear the DTC with the HDS.
- Start the engine, and let it idle for 10 seconds or more.
- 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 CKP sensor, the throttle body, the MAF sensor/IAT sensor, ECT sensor 1, ECT sensor 2, and the PCM. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION or NOT COMPLETED, go to step 6.
- Inspect the ignition timing (see
IGNITION TIMING INSPECTION
).
Is the ignition timing OK?
YES -Go to step 12.
NO -Go to step 11.
- Check for damage at the CKP sensor (see
CMP SENSOR REPLACEMENT ) and the CKP sensor pulser plate (see
CKP PULSE PLATE REPLACEMENT
).
Is the CKP sensor or the CKP sensor pulser plate damaged?
YES -Replace the CKP sensor (see CMP SENSOR REPLACEMENT ) and/or the CKP sensor pulser plate (see CKP PULSE PLATE REPLACEMENT ), then go to step 21.
NO -Go to step 28.
- 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 (see THROTTLE BODY REMOVAL/INSTALLATION ), then go to step 21.
- Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.
- 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 4.7-5.7 gm/s?
YES -Go to step 15.
NO -Replace the MAF sensor/IAT sensor (see MAF SENSOR/IAT SENSOR REPLACEMENT ), then go to step 21.
- Turn the ignition switch to LOCK (0).
- Allow the sensors to cool to the ambient temperature.
- Note the ambient temperature.
- Turn the ignition switch to ON (II).
- Quickly note the value of ECT SENSOR 1 and ECT SENSOR 2 in the DATA LIST with the HDS.
- 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 21.
NO -Refill the coolant (see COOLANT CHECK ), then check for and repair any problems with the following items, and go to step 21.
- Engine compression and cylinder leak down
- VTEC system
- Engine oil
- A/C system
- Power steering
- Turn the ignition switch to ON (II).
- Reset the PCM with the HDS.
- Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
- Let the engine cool until the value of ECT SENSOR 1 is 122°F (50°C) or less.
- Start the engine, and let it idle for 10 seconds or more.
- 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 PCM, then go to step 1.
NO -Go to step 27.
- 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 PCM, then go to step 1. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION or NOT COMPLETED, go to step 24.
- Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
- Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
- Let the engine cool until the value of ECT SENSOR 1 is 122°F (50°C) or less.
- Start the engine, and let it idle for 10 seconds or more.
- 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 PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 30. If the PCM was substituted, go to step 1.
NO -Go to step 33.
- Monitor the OBD STATUS for DTC P050B in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ). 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 PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 30. If the PCM 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 or NOT COMPLETED, go to step 30.