From the 2014 service manual:
P0351 - Ignition Coil A Primary/Secondary Circuit
Description: This DTC sets when the PCM does not receive a valid ignition diagnostic monitor (IDM) pulse signal from the ignition module PCM.
Possible Causes:
- VPWR circuit open
- VPWR circuit short to ground
- COP1 circuit open (COP)
- CDA circuit open (coil pack)
- COP1 circuit short to voltage (COP)
- CDA circuit short to voltage (coil pack)
- COP1 circuit short to ground (COP)
- CDA circuit short to ground (coil pack)
- Damaged COP (if equipped)
- Damaged coil pack (if equipped)
Diagnostic Aids: The DTC P0351 only sets for a coil primary circuit failure. A secondary ignition coil or spark plug failure does not set the DTC P0351. The DTC P0301 does not set for a coil primary circuit malfunction. The DTC P0351 may set with or without the DTC P0301, however the DTC P0351 sets first.
When this DTC is set, the PCM enters failure mode effects management (FMEM) which shuts down the injector for the associated cylinder in order to protect the catalytic converter. This is normal operation, do not attempt to diagnose the injector with this DTC present.
If a primary coil is damaged due to a harness short to ground the PCM will not be damaged. Do not replace the PCM without verifying the coil driver functionality.
Use the 12-volt non-powered test lamp to verify VPWR voltage at the ignition coil harness connector.
Check the coil driver circuit for open, short to voltage, or short to ground.
P0353 - Ignition Coil C Primary/Secondary Circuit
Description: This DTC sets when the PCM does not receive a valid ignition diagnostic monitor (IDM) pulse signal from the ignition module PCM.
Possible Causes:
- VPWR circuit open
- VPWR circuit short to ground
- COP3 circuit open
- COP3 circuit short to voltage
- COP3 circuit short to ground
- Damaged COP
Diagnostic Aids: The DTC P0353 only sets for a coil primary circuit failure. A secondary ignition coil or spark plug failure does not set the DTC P0353. The DTC P0303 does not set for a coil primary circuit malfunction. The DTC P0353 may set with or without the DTC P0303, however the DTC P0353 sets first.
When this DTC is set, the PCM enters failure mode effects management (FMEM) which shuts down the injector for the associated cylinder in order to protect the catalytic converter. This is normal operation, do not attempt to diagnose the injector with this DTC present.
If a primary coil is damaged due to a harness short to ground the PCM will not be damaged. Do not replace the PCM without verifying the coil driver functionality.
Use the 12-volt non-powered test lamp to verify VPWR voltage at the ignition coil harness connector.
Check the coil driver circuit for open, short to voltage, or short to ground.