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gomi_otaku
gomi_otaku, VW Technician
Category: VW
Satisfied Customers: 3379
Experience:  VW FastTrack '00-'01, VW Academy Chicago and Seattle '00-present, VW Certified
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2003 VW Passat is giving P351,P352, codes. Engine is

Customer Question

2003 VW Passat is giving P351,P352, codes. Engine is otherwise running smoothly. I would like to troubleshoot to avoid additional Check Engine Light (CEL). CEL reappairs quickly after reset.
Submitted: 1 year ago.
Category: VW
Customer: replied 1 year ago.
Code update: P351,P352, P353, P491, P492, P2181. The ignition coil codes P35x return immediately, the others take longer and I need to verify how quickly they return after reset.
Expert:  Dan replied 1 year ago.

Hello, my name is***** anything been replaced yet? Thanks.

Customer: replied 1 year ago.
July, car stopped running. Replaced plugs, wires, and ignition coil pack. Then traced problem back to open in wire controlling relay to ignition coil pack and repaired.
Expert:  Dan replied 1 year ago.

So problem is taken care of as of now?

Customer: replied 1 year ago.
Code update: P351,P352, P353, P491, P492, P2181. The ignition coil codes P35x return immediately, the others take longer and I need to verify how quickly they return after reset.
Expert:  gomi_otaku replied 1 year ago.

The P0491 and 0492 are caused by a buildup of carbon in the channels in the head for the secondary air system. It requires you to bore these channels back out with an extra long drill bit of the appropriate size.

The P2181 is usually caused by a thermostat that is sticking open slightly, just enough that the engine does not warm up according to a timed map in the ECM. Often we replace the thermostat and the engine coolant temp sensor on the back of the head at the same time.

The coil issues are all on the same side- have you checked for any other wiring damage in the harness?

Customer: replied 1 year ago.
Thanks for the info on the codes and possible causes. the P351,2,3 is occuring most frequently and immediately following a code clear.You mentioned " coil issues are all on the same side". I understand that there are only three coils (not six) because each coil is shared by two cylinders.
Expert:  gomi_otaku replied 1 year ago.

Have you checked the wiring to the coil pack? I don't understand how the car can be running smooth with a coil issue for 3 cylinders! Have you tried doing a capacitive discharge to make sure the codes are not just "burned" into the memory? After clearing faults, disconnect the battery, touch the cable ends together for about a minute, then reconnect. This will reset all modules