QuestionQUESTION: Hello Kevin
I have a very well discussed fault with a 2001 model UK import Neon SE. The speedo reading is not registering, and the transmission fails to change up. So far I have checked the engine / trans earth strap to the underside of the battery tray and added an extra large gauge strap. I just went out in it for a mile or so, after having disconnected the battery, and no codes were registered except 1684. Sometimes I have had the engine check light come on, and 1698 register. The TCM is receiving an alternating signal from the o/p speed sensor when the front wheels are turning. The TCM has all correct 12v and earths. The TCM has suffered a very slight ingress of salt / water, but gel membrane appears in tact. There is pulsing signal on the comms line to the TCM. I need to get a scope probe to it. My question is - how does the speed signal get to the cluster, and does it go thru the TCM? If so where does it leave the TCM? Also defective solder joints on the cluster board are much discussed on the www - could this cause P1698 and no shift from 1? I can pick up a used TCM, but I understand EPROM needs to be updated with the VIN etc. This is a base model though with no fancy security system to my knowledge. Does the TCM still need updating in this case? I can't tell you how grateful I would be for your insight or even a cct diagram for the speed signal path. Many thanks in advance MH
ANSWER: Hi Mark,
I have the '01 Neon manual but it doesn't show the electronic transaxle to be in use yet for that model year. Rather it shows the three-speed non-electronic transaxle, so the export version may be 'ahead' of the domestic, though I personally would rather have the non-electronic. But I believe that we have an issue with terminology because in '04 manual I see a TE40 trans which is four speed and hydraulically controlled but does have some adaptive electronic controls and sensors and an integral PCM/TCM. Do you have such a single control module and if so how many plugs/pins per plug do you have so I can be sure that the '04 applies to your '01 vehicle. Also, which size engine do you have?
Roland
PS Sorry for the delay but I just found your question in the 'pool' to which it had been referred by Kevin.
---------- FOLLOW-UP ----------
QUESTION: Hi Roland
Great to be in touch again, and I hope that you are very well. Thanks a lot for coming back to me. Re export Neons running ahead of the domestic unit specification - I had independently come to exactly the same conclusion. It is Neon SE Auto 4 door saloon 1995 cc VIN 1C3EVB6C61D115978 It has two u-processor control modules mounted either side of the radiator. Unbelievably, the loom connecting the two runs along the underside of the radiator. The output speed sensor wire is double protected by an extra inner conduit (in Chrysler's defence) and it is in tact. The TCM sits behind the right side (driver side in UK) headlight, screwed alongside the washer bottle. The TCM has a single multi-pin connector P/N P05033790AF. I have photos of both trans and powertrain control modules. PCM (left side) has two connectors P/N P05033058AG. At the TCM connector, I found 12V and earth connections in all the expected places. Ditto the o/p speed pulses, and some kind of alternating signal on the bus (no scope with me at the time - only DVM) My personal belief (I am usually wrong / over optimistic)is that if we can restore the speed reading, at the cluster, all will be well again. The clock exercise routine by holding in the trip reset, shows that all gauge needles are functional. My belief in simple solutions to complex-seeming fault symptoms is unwavering .. so far. Grateful for your input. Kind regards
mark h
ANSWER: Hi Mark,
I wonder if the "Neon" you have might actually be what we call here a Cirrus/Stratus or a Sebring? What are the first 11 digits of the Vehicle Identification Number and what sort of ID plate numbers are on the transmission case? Rather than guessing about what you have there it would be most likely I can be specific once a good ID is in hand. I would like to be able to use one of my several manuals that apply to the powertrain you actually have there.
Roland
PS Thanks for the kind remarks and nomination.
---------- FOLLOW-UP ----------
QUESTION: Hi Roland
Thanks for your reply. It's def a Neon. Neon shape but in England marketed as a Chrysler product VIN 1C3EVB6C61D115978. Have to go out now, back midnight GMT Cheers M
AnswerHi Mark,
I did find in the '04 Neon manual that the V in position 5 does indicate it is a RHD Neon. The B does mean a 4-speed automatic, but the transmission does not have a separate control module because it is not a fully electronic transaxle for that year at least. So can you get any indication of a trans model from an ID plate on the transmission? Also, how many plugs and how many pins/plug are on the pcm and the tcm.
I did also find in my '02 manual for the PT Cruiser which uses the 2.0L with an ETAX 41TE transmission that the 1698 implies a communication of the digital data between the TCM and the PCM is the issue. On that set up though the output speed sensor signal is not digitized on the bus but rather goes on a separate wire from pin 58 of the TCM (white/orange wire) to pin 66 at the PCM. At the PCM it is then digitized and sent with much other data to the cluster. See if your wiring looks anything like this and if so check the wire. It could be that either the PCM or the TCM is at fault. But at least I may have some wiring diagrams to work with you.
Roland
