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 No Signal
- Turn the ignition switch ON (II).
- Clear the DTC with the HDS.
- Start the engine.
- Check for Temporary DTCs or 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 the CMP sensor and the PCM.
- Turn the ignition switch OFF.
- Disconnect the CMP sensor 3P connector.
- Turn the ignition switch ON (II).
- Measure voltage between CMP sensor 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 open in the wire between the CMP sensor and under-hood fuse/relay box (PGM-FI main relay 1), then go to step 18.
- Measure voltage between CMP sensor 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 voltage between CMP sensor 3P connector terminals No. 2 and No. 3.
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Is there battery voltage?
YES - Go to step 16.
NO - Repair open in the wire between the CMP sensor and G101, then go to step 18.
- Turn the ignition switch OFF.
- Jump the SCS line with the HDS.
- Disconnect PCM connector B (49P).
- Check for continuity between PCM connector terminal B46 and CMP sensor 3P connector terminal No. 1.Fig 4: Identifying Continuity Between PCM Connector Terminal B46 And CMP Sensor 3P Connector Terminal 1
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES - Go to step 15.
NO - Repair open in the wire between the PCM (B46) and the CMP sensor, then go to step 18.
- Check for continuity between CMP sensor 3P connector terminal No. 1 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES - Repair short in the wire between the PCM (B46) and the CMP sensor, then go to step 18.
NO - Go to step 26.
- Turn the ignition switch OFF.
- Replace the CMP sensor (see CMP SENSOR REPLACEMENT ).
- Reconnect all connectors.
- Turn the ignition switch ON (II).
- Reset the PCM with the HDS.
- Clear the CKP pattern with the HDS.
- Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
- Do the CKP pattern learn procedure (see CRANK (CKP) PATTERN CLEAR/CRANK (CKP) PATTERN LEARN ).
- Start the engine.
- Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0340 indicated?
YES - Check for poor connections or loose terminals at the CMP sensor and the PCM, then go to step 1.
NO - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTCs 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 Temporary DTCs or DTCs with the HDS.
Is DTC P0340 indicated?
YES - Check for poor connections or loose terminals at the CMP sensor 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 Temporary DTCs or DTCs are indicated, go to the indicated DTCs 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.