Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0340: CMP Sensor A No Signal
- Turn the ignition switch to ON (II).
- Clear the DTC with the HDS.
- Start the engine.
- Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0340 indicated?
YES -Go to step 5.
NO -Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at CMP sensor A and the PCM.
- Turn the ignition switch to LOCK (0).
- Disconnect the CMP sensor A 3P connector.
- Turn the ignition switch to ON (II).
- Measure the voltage between CMP sensor A 3P connector terminal No. 3 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
YES -Go to step 9.
NO -Repair an open in the wire between CMP sensor A and the No. 3 ALTERNATOR (10 A) fuse, then Go to step 18.
- Measure the voltage between CMP sensor A 3P connector terminal No. 1 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there about 5 V?
YES -Go to step 10.
NO -Go to step 11.
- Measure the voltage between CMP sensor A 3P connector terminals No. 2 and No. 3
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
YES -Go to step 16.
NO -Repair an open in the wire between CMP sensor A and G101 (see STARTER SUBHARNESS ('07-09 MODELS) ), then Go to step 18.
- Turn the ignition switch to LOCK (0).
- Jump the SCS line with the HDS.
- Disconnect PCM connector C (49P).
- Check for continuity between PCM connector terminal C45 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Repair a short in the wire between the PCM (C45) and CMP sensor A, then Go to step 18.
NO -Go to step 15.
- Check for continuity between PCM connector terminal C45 and CMP sensor A 3P connector terminal No. 1.Fig 5: Checking Continuity Between PCM Connector Terminal C45 And CMP Sensor A 3P Connector Terminal No. 1
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Go to step 23.
NO -Repair an open in the wire between the PCM (C45) and CMP sensor A, then Go to step 18.
- Turn the ignition switch to LOCK (0).
- Replace CMP sensor A (see CMP SENSOR A REPLACEMENT ).
- Reconnect all connectors.
- Turn the ignition switch to ON (II).
- Reset the PCM with the HDS.
- Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
- Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0340 indicated?
YES -Check for poor connections or loose terminals at CMP sensor A and the PCM, then Go to step 1.
NO -Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.
- Reconnect all connectors.
- Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
- Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0340 indicated?
YES -Check for poor connections or loose terminals at CMP sensor A and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the PCM was substituted, Go to step 1.
NO -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 are indicated, go to the indicated DTC's troubleshooting.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.