DTC P0340, P0344: CMP Sensor A No Signal, CMP Sensor A Intermittent Interruption

Reset the ECM/PCM (see HOW TO RESET THE ECM/PCM ).
Start the engine.
Is DTC P0340 and/or P0344 indicated?
1. YES - Go to step 3.
2. NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the CMP sensor A and at the ECM/PCM.
Turn the ignition switch OFF.
Disconnect the CMP sensor A 3P connector.
Turn the ignition switch ON (II).
Measure voltage between CMP sensor A 3P connector terminal No. 3 and body ground.

Fig 1: Measuring Voltage Between CMP Sensor A 3-Pin Connector Terminal No. 3 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Go to step 7.
2. NO - Check the No. 4 ACG (10A) fuse in the underdash fuse/relay box. If the fuse is OK, repair open in the wire between the CMP sensor A and No. 4 ACG (10A) fuse.
Measure voltage between CMP sensor A 3P connector terminal No. 1 and body ground.

Fig 2: Measuring Voltage Between CMP Sensor A 3-Pin Connector Terminal No. 1 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there about 5 V?
1. YES - Go to step 8.
2. NO - Go to step 10 .
Measure voltage between CMP sensor A 3P connector terminals No. 2 and No. 3.

Fig 3: Measuring Voltage Between CMP Sensor A 3-Pin Connector Terminals No. 2 & No. 3
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Go to step 9.
2. NO - Repair open in the wire between the CMP sensor A and G101.
Substitute a known-good CMP sensor A and recheck.
Is DTC P0340 and/or P0344 indicated?
1. YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck (see ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/ indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
2. NO - Replace the original CMP sensor A (see VTEC Solenoid Valve Removal/Inspection ).
Measure voltage between ECM/PCM connector terminal A25 and body ground.

Fig 4: Measuring Voltage Between ECM/PCM Connector Terminal A25 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there about 5 V?
1. YES - Repair open in the wire between the ECM/ PCM (A25) and CMP sensor A.
2. NO - Go to step 11.
Turn the ignition switch OFF.
Disconnect ECM/PCM connector A (31P).
Check for continuity between ECM/PCM connector terminal A25 and body ground.

Fig 5: Checking Continuity Between ECM/PCM Connector Terminal A25 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Repair short in the wire between the ECM/ PCM (A25) and the CMP sensor A.
2. NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck (see ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/ indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.