While driving my car, it suddenly slowed and then the engine quit. I was able to restart it and drive home. The warning light indicated there was a problem with the ECM. I had a telematics device installed that gave the same message. So not to get stranded on the way, I took the car to the closest garage to me and told them the history of what happened. They had the car for 4 days and replaced spark plugs, ignition coils, etc but the PCM light remained on. They returned the car to me (along with a $1500 bill) with the admonition not to drive too far. They had checked with VW and the part needed is on back order with no availability date. This garage suggested that they could buy a used part and rebuild it and they would need my car for 2-3 weeks. I declined and took my car to the VW dealership. I told them the whole history and they scanned the car and told me I needed a new frt O2 sensor! ($680) When I inquired why that hadn’t come up before, they told me it was a new problem. So, the power control module light is still on and it seems as though no one really knows what’s going on.
The car is running but is misfiring just like in the beginning. I’m afraid to drive it anywhere! Any insight or advice you can gi
First off, you are seeing a check engine light or CEL. That light comes on when the engine computer recognizes a fault. It stores a code that the mechanic uses to help diagnose the problem. The actual codes would help us better understand the problem.
If it was just bad ECM, why did mechanic one change all those parts but not the ECM? Sounds like they were throwing your money at the problem hoping something would stick.
If, indeed, you need a new engine control module (ECM) I would recommend a new one from VW first and a rebuilt one only if you have no other choice. An internet search may find a new part on someone’s shelf.
First of all, I would only accept a “bad ECM” as a diagnosis if the reason given is something like “ECM fails to output such-and-such voltage or signal on such-and-such wire, and the wiring harness has been inspected” and I would not accept this diagnosis if the reason given is something like “we tried everything else, so it must be the computer”. Often times, a damaged wiring harness is the actual problem, and this could be the result of an open circuit due to a wire breaking inside a jacket or bushing, or a short/leakage to ground caused by a wire rubbing through or being chewed on by rats/mice.
Second, the replacement of basic “tune-up parts” such as the spark plugs and ignition coil(s) should not cost anywhere close to $1500, and such a high repair bill with no resolution is unacceptable in my opinion.
Third, even a basic $100 scan tool with live data capability should provide some insight as to what is causing the misfire, and a professional shop with access to a professional-level scan tool should be able to get to the bottom of this. Even with my inexpensive scan tool, I can observe parameters such as coolant temperature, intake air temperature, intake manifold pressure (vacuum), engine RPM, engine load percentage, detected throttle position, short-term fuel trims, long-term fuel trims, misfire counters, etc. Interpreting this information should allow a mechanic to zero in on what exactly is causing the misfire: lack of fuel at the proper time, lack of spark at the proper time, faulty sensor data (perhaps due to defective wiring), insufficient cylinder compression (which may be intermittent in the case of a cracked cylinder head, head gasket leak, or valve which is not closing properly).
At this point, we are not even certain that the PCM is the problem, and unless it can be proven that the PCM is failing to pulse one or more fuel injector(s) or spark plugs, I doubt that it is. It is much more probable that a vacuum leak, faulty sensor reading due to defective wiring, or mechanical problem inside the engine is the real problem.
One component that can fail and stump mechanics is a crankshaft position sensor.
The reason being, as the article states, is because it doesn’t always cause the Check Engine light to turn on.
So, for most mechanics, unless there’s a code indicating a possible cause for the problem, they just stand their scratching their butts.
So, the Check Light can be on for a totally different reason, while crank sensor is still causing problems.
Tester
Sure, and it’s cheap enough to replace, especially if you buy the part online and DIY. However…proper use of even a $100 scan tool should be able to confirm or rule out this possibility. If the crankshaft position sensor and/or associated wiring is defective, the tachometer signal will be lost, or erratic.
Really great input and suggestions. Thank you!
FYI - initial scanned codes were p0606, p3096, p06d1
The 2013 Jetta had a lot of engine options. I don’t see the latter two codes applicable for the L4-2L engine. The first code applies to that engine, is for a faulty ECM. Just to make things more interesting, it appears p0606 could also apply to the transmission. Go figure.
If your problem is the ECM (engine control module) is plain kaput, about the only alternatives are a new one from VW, a used one from a wrecked similarly configured 13 Jetta, or see if there are any aftermarket versions available, like from Summit Racing.
Concur w/ @Mustangman above, I don’t understand why throw a bevy of replacement parts at a kaput ECM. First step is installing a good ECM, then can start w/the parts throwing if no better ideas.
For better help here, suggest to post your car’s engine & transmission configuration. If don’t know, open the hood, needed info should be on a sticker on the underside of hood.
Did anything unusual occur to electrical system just prior to this symptom? Like getting/giving a jump-start, replacing battery or alternator?
PCM’s are basically small computers, and like most computers, they would usually have the ability to test themselves. One self- test might be to see if a test input number produces the correct output number. Similar to a check-sum. If it won’t pass that sort of test, very likely an internal problem with the ECM, requiring ECM replacement. No idea how a tech would ID an internal ECM problem with some other sort of problem though. Good idea to first check ECM power and ground is correct I guess. Single point failure. Problem just goes with the computerization of cars. Computer no good, car no good.