DTC P0641: Sensor Reference Voltage A Malfunction Acura TL IV facelift

Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Scheme 179

Scheme 180

Scheme 181

1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
2. Clear the DTC with the HDS.
3. Check for Pending or Confirmed DTCs with the HDS. Is DTC P0641 indicated? YES - Go to step 4. NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the ECM/PCM and these parts: • Throttle body EGR valve Input shaft (mainshaft) speed sensor APP sensor
4. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
5. Disconnect the connectors of these parts: Throttle body EGR valve Input shaft (mainshaft) speed sensor APP sensor
6. Turn the ignition switch ON (II), or press the engine start/stop button to select the ON mode.
7. Clear the DTC with the HDS.
8. Check for Pending or Confirmed DTCs with the HDS. Is DTC P0641 indicated? YES - Go to step 10 . NO - Go to step 9.
9. Check for Pending or Confirmed DTCs with the HDS while reconnecting these parts, one at a time: Throttle body EGR valve Input shaft (mainshaft) speed sensor APP sensor Is DTC P0641 indicated? YES - Replace the part that caused the DTC when it was reconnected, then go to step 14 . NO - Check for poor connections or loose terminals at the ECM/PCM and the following parts, then go to step 1 . Throttle body EGR valve Input shaft (mainshaft) speed sensor APP sensor
10. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
11. Jump the SCS line with the HDS.
12. Disconnect ECM/PCM connectors A (49P), B (49P), and C (49P).
13. Check for continuity between body ground and ECM/PCM connector terminals A24, B18, and C12 individually. Is there continuity? YES - Repair short in the wire between the ECM/PCM (A24, B18, or C12) and each part that was disconnected in step 5 , then go to step 14. NO - Go to step 20 .
14. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
15. Reconnect all connectors.
16. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
17. Reset the ECM/PCM with the HDS.
18. Do the ECM/PCM idle learn procedure (see «ECM/PCM IDLE LEARN PROCEDURE»(ref-512362-S04299387872012103100000) ).
19. Check for Pending or Confirmed DTCs with the HDS. Is DTC P0641 indicated? YES - Check for poor connections or loose terminals at the ECM/PCM and the following parts, then go to step 1 . Throttle body EGR valve Input shaft (mainshaft) speed sensor APP sensor NO - Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.
20. Reconnect all connectors.
21. Update the «ECM/PCM»(ref-512332-S15795428962012103100000) if it does not have the latest software (see «ECM/PCM Update»(ref-512332-S15795428962012103100000) ), or substitute a known-good ECM/PCM (see «SUBSTITUTING THE ECM/PCM»(ref-512356-S00793962012012103100000) ).
22. Check for Pending or Confirmed DTCs with the HDS. Is DTC P0641 indicated? YES - If the ECM/PCM was updated, substitute a known-good ECM/PCM (see «SUBSTITUTING THE ECM/PCM»(ref-512356-S00793962012012103100000) ), then recheck. If the ECM/PCM was substituted, check for poor connections or loose terminals at the ECM/PCM and the following parts, then go to step 1 . Throttle body EGR valve Input shaft (mainshaft) speed sensor APP sensor NO - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original «ECM/PCM»(ref-512332-S08907075282012103100000) (see «ECM/PCM Replacement»(ref-512332-S08907075282012103100000) ). If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.