Can a tps problem cause ecm to go bad?
 

hi all,
ok I somehow had the wired pulled out of tps and have fix that problem except that now i get no spark, no power to tps, throttle body motor, ignition module, ckps, but do have power going to fuel pump. do you think that when the wires got yanked out that it shorted out the ecm? or could it be something else. I took off the ecm and checked continuity like on tps wires the go in and come out and It seems ok had 1 ohm only. I checked all the circuit and found that the green ground wire to the thottle position motor has a bad ground, but I cant find where it was bad at. I checked all the relays and all fine even tried switching them around. tripple checked all fuses. If I put a wire from pos. side of relay to neg, side on coil relay then I get spark ( what ecm is supposed to do) so that tells me that ignition coils are good. I cant pull no codes because I think ecu is bad so my odb reader is just sits there wating for the car to respond. anyone with any Ideas whats going on? need all helpI can get. I have jtis cd and check a few things from there and cant figuer it out going krazy help please!!!!!!!!!!!!!!!!!

ps:car is a 1998 xk8 and messages are stability control failer, amber failsafe, gearbox fault, incorrect part fitting, and before all this I had none.

Ed, I would be venturing to guess that the power wire you are bypassing to make the car run has been strained and you have managed to break the wire inside the insulation, leading to a high resistance connection. This can only show up when current is passing through the wire. I see this occasionally at work. I would first start by running a new wire from the last plug back up to the TPS and see how the car runs then.

If the car was running (ie, key in the "RUN" position) when the wire was pulled out, then it is very possible that you could have hurt the ECM. If the car was turned off when the wires got yanked, then I would be looking at a damaged wire as your problem.

hi thermo
 

yes, it was running when it died and i saw that wires were pulled out and I checked them for hi resistance after i fixed the and all were ok so i will buy a new ecm thanks.

new ecm
 

hi thurmo,
hey I installed a new ecm but the part #'s were a little different. Now I get fuel, power to vvt's, ecmt(emct?),masft,and tps and throttle body motor, but not to crank senors, or to ignition modules. Shows no code or error mesages . I called a jag dealer and they said I need to have re-progammed and maybe immobilizer re-set. but my key and fob both work. what do u think?


ps. my ecm part # is LNC1410/AJ and new is #LNC1410/GB

Ed, based on what you are describing, you are getting a security issue going on and the computer is not reading the proper code inside the key. So, you may want to try talking to a local lock smith and see if they can program your keys to the car. If not, you will be stuck with having the car towed to the dealership and having them program the key(s) to the car. I wish the news was better, but that is what it is looking like.

re
 

I dont know about that cause it worked before the short-out. would the car start with the security module diconnected?

crank sensor
 

could a bad crank sensor cause my no fire poblem?

ed, with the security module disconnected, that should have no effect on the ability of the car to start as the start signal does not go through the security module. The ECM puts out a signal to the key and then the key responds with its code which is then recieved back by the ECM.

As for the bad crank sensor, it will only throw a code as the ECM can determine the position of the engine (while not as accurately) by using the camshaft position sensors. This is part of the redundancy built into the cars so that a single failure will not prevent the motor from running.

im disqusted
 

I cant figuer it out. I found out the ecm I bought was from a 1998 xj8 and not an xk. I looked at the wiring on both and there's only 3 wires that were different going into ecm em10-22, em13-9, i 4got the other but 1 is just a different color but to the same thing the other 2 are not listed in the xj. so maybe i have find the right 1.

thanks thermo

I think you'll feel better edsterp if you can get an ECM with your matching part number, or did you try having it rebuilt? Could be much cheaper. There's a thread in the XK8 section (sick kitty I think) that shows a member who fixed his own for about $5 and some soldering skills.