Question1997 Chrysler LHS - 3.5 Motor
On mother's day of all days the car went into limp mode. It seems to shift fine manually but obviously once it goes into limp mode it will not shift beyond the single gear allowed in order for me to limp home. I highly suspect that there is something electrical going on and not actual hard trans damage of any kind but I could of course be wrong. I had the system scanned with one of those heavy duty scanners and these are the codes that it tossed in my direction...
12 - Battery Power To Mod Disconnected
29 - TPS Signal
36 - Fault Immediate After Shift
53 - Gear Ratio Speed In 3rd
54 - Gear Ratio Speed In 4th
74 - Calculated Oil Temp In Use
I believe that 36,53,54 are the only codes that can send the trans into limp mode but not so sure about that so hoping someone might have some advice there too but what I mainly need to know is what I should be trying to do next to fix this issue so the car will safely come out of limp mode. I need to get the vehicle up and running without being ripped off and without wasting money trying to fix the wrong things, so any suggestions or advice would be greatly appreciated.
UPDATE: We replaced input and output speed sensors and that did not fix issue. Nor did trying another computer brain or EATX relay fuse. So now we are really lost and running out of options.
AnswerHi Sammantha,
The manual states that when you have a 36 code there will be other codes and when looking at the other codes do not consider electrical or hydrualic issues as causitive, only mechanical issues. The 53 and 54 codes also point only to mechanical problems internal to the transmission. That would point to their being something wrong inside the transmission rather than an electrical problem.
The 29 code will cause the transmission to not shift into fourth gear, which is of course not the same as limp-in mode which only allow it to go to second gear. So you would do well in any case to try and fix that lack of the throttle position sensor signal. That signal comes from pin 2 (orange/dark blue wire) of the tps plug and goes to a splice where is splits to send the signal to the engine control module (ecm) (pin 22 at the ecm) also and goes through a 4-pin black disconnect (only 3 wires in use) near the tcm and arrives on pin 12 of the tcm plug on a orange/dark blue wire. Why don't you see if that wire connection from the tps plug to the tcm pin and the ecm pin is patent and if not trace it and find out why. The tps could be defective. If so, then you might also see a code 24 on the ecm memory which you can check by using the ignition switch (on-off-on-off-on and leave on in 5 seconds or less, then count the flashes of the check engine light) to do the engine fault code readout.
You might be lucky and find that would correct the situation, but it is a 'long shot'.
If the transmission has 100,000+ miles on it you are probably looking at an internal clutch failure or some similar mechanical problem that would require a rebuild because of the 36,53 and 54 point that way. Let me know how this works out, please.
Roland
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