Magneti Marelli ignition coils ALFA ROMEO 156 (932)
30.07.21
08.08.25
@Anna Johnson03.08.2021 10:43AUTODOC expertCauses of the P0351 codeDefective spark plugs or damage to tied wiresIgnition coil defectiveDefective ECMShort circuit or open circuit in the ignition coil wireBad electrical connectionWhat repairs can fix the P0351 code?Replacing spark plugs and related wiresReplacing the ignition coilRepair or replace worn or damaged electrical wiresRepair or replace the damaged electrical connectorReplacing the engine control unit------------------P0354The P0354 code indicates that the vehicle PCM is not receiving the required signals from the ignition coil or coils while the vehicle is in use. This could indicate a problem with the primary or secondary winding of the coil.To resolve the P0354 code, you may need to:Eliminating intake manifold vacuum leakageRepair or replace worn or damaged ignition coil wires (or coils)Replacing one or more spark plugsRepair or replacement of one or more ignition coils- @secret_m08.08.2025 15:59MemberYour issue with the constant “check engine” MCSF warning and fault codes P0351 to P0354 (No Signal Present on all four Marelli ignition coils) after replacing Bosch coils with Marelli ones on your 2005 Alfa Romeo 156 JTS is a known problem experienced by some users.
The main points are:
- The Marelli coils may not be fully compatible or properly recognized by the car's ECU compared to the Bosch coils originally fitted. This lack of recognition causes the ECU to log ignition coil circuit faults (P0351-P0354) even though the engine runs fine on emergency mode.
- Simply clearing the codes with a scanner or resetting the ECU by disconnecting the battery does not permanently solve the issue.
- The problem seems to be that the Marelli coils do not send the exact signal or electrical response expected by the ECU, which leads it to believe no signal is present.
Potential solutions or next steps that have been discussed in Alfa Romeo owner forums include:
- Reverting to the original Bosch coils if possible, as they do not trigger these fault codes.
- Checking wiring and connectors for any installation issues, though this is less likely since codes appeared only after coil change.
- Some users have reported that aftermarket Marelli coils (even if branded) can have slight differences in coil primary resistance or signal characteristics causing ECU incompatibility.
- Unfortunately, there is no official or straightforward procedure to "reprogram" the ECU to accept the Marelli coils.
In summary, the likely cause is an incompatibility between the Marelli ignition coils and the Alfa 156 JTS ECU, resulting in persistent P0351-P0354 errors despite the coils physically working. The most reliable fix is to use the Bosch coils or Marelli coils verified as fully compatible replacements for your model.
These were put into the car a few days ago and although the car runs fine, the check engine light is constantly on and I am getting faut codes P0351 – P0354 No Signal Present – on all 4 of the Marelli coils. This did not happen with the Bosch ignition coils previously fitted and has only occurred when these were changed to the Marelli ones.
No other faults show up, other than these – the car apparently runs fine because it is on the emergency program, but the fault codes cannot be permanently deleted simply by clearing codes with the scanner.