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Continue TPS part 2

(1999 Mazda Protege)
in Averill Park, NY on January 13, 2011
Status to date: The original TPS was bad. Voltage was way off normal. I had put a NAPA replacement in but that unit was asssembled wrong. At Idle it was reading the voltage you would have going down the highway. The new factory unit "had" correct voltage and when first installed, acted fine. I stop to pick-up the car and the light goes on again along with blinking Over Drv indicator.We test drive the car but the voltage now begins to fluxuate on the new TPS. I left the car there as the mechanic wants to think whats occuring thru.
Displaying 2 answers & 5 comments
Popular Answer
on January 13, 2011
Have the shop check the wiring for the TPS. Also, the blinking O-DRV light is a Transmission issue, have the codes for the transmission been checked? Because, they need to be.
on January 13, 2011
I posted another question after this one. The shop owner placed a independant ground on the tps connector (as you suggest, ie "check the wiring) That seemed to solve the problem. Car shifts normal now as of his test drive. I haven't gotten the car back yet. I had checked for a ground with a static engine. We found that the code was thrown as soon as the car was put into gear and acelerated. Possible engine torque movement ?
The first TPS (Original was way off voltage) Could voltage surge "cook" it. Thanks much Dan, I was able to assist my mechanic with the input I got from you guys. I will suggest about checking the tranny codes for the sake of information. This has been quite a process.
on January 13, 2011
Dan -- From the previous posts, I had mentioned the trans codes, and Cpete had assured me that there was only the P0123. Doing a little bit of checking, it's plausible that the P0123 could in some cases flash the OD light, in as much as the transmission is concerned about the abnormally high TP reading. I would have expected a P07xx code or something, but if he says it was only a P0123............. Anyway, glad to see you're on the path to repair, Cpete.
on January 14, 2011
Trust me , Dave it only showed the one code. I want to thank you guys for the input. I built 2 street rods back in the late 70's so I'm not totally foreign to cars. This new stuff is a challenge.....The latest mech did not have a breakout box. (Miscommunication) Would that have helped in the diagnostics ? Should I continue to look for the fault in the harness or is this fix sufficient. I'm getting the car today, hope to report back. Hopefully, someone else might benefit from all this communication, this has been a a tad much to deal with. Can't say thank you enough for the help. Chris
on January 14, 2011
I trust you, Cpete! I was only passing the info along to Dan, who was concerned about a trans code along with the TP code. You would have gotten any trans codes with the P0123 if there were any.

Break out boxes basically give you the ability to check the harness and such by way of providing a consistent usable surface to do continuity and circuit testing. Without a BOB, you can't be sure you are able to check the power of the TP via the PCM. The BOB connects to the PCM and then the harness to the PCM connects to the BOB...

As new cars today go with active commanding paramaters via a diagnostic tool, BOB's are less and less prevalent in the reapir shops.

If you are still getting a failure code and / or an OD light flashing, the problem is indeed not resolved. If all is well - then I would stop looking further at this time.
on January 14, 2011
Thanks so much Dave. I got the car back today and it runs great. I mentioned in other posts that the "bad" cirucit is still there but my mech cut the wire at the connector and ran a separate new ground to the block. No more lites, codes or flashing indicators. The car is a pleasure to drive again! I'm tempted to research the now deactive ciruit just for information sake. There is a slight concern that whatever caused the original short could continue as time progresses. Thank you very much for the time an effort you put in on this problem. Your effort hasn't gone to deaf ears. I value the opportunity to learn from technicians like yourself. I hope I was a decent student. Thanks again Chris
on January 14, 2011
Chris, it's all good; glad you are back on the road trouble free.

To be honest, many "unknown" wiring issues are solved by doing what your tech did - overlaying the circuit. Yes, curious minds prevail and want to know what happened, but at the end of the day, if the repair is complete...sometimes it's better to move on with life with the satisfaction that the problem is solved.

Technicians work for efficiency's sake for their own good and for the good of the paying consumer. This is why an overlay is often most reasonable when you have an involved circuit that has an intermittent harness issue. In any case, good job, and glad you are on the road. Thanks for visitng RepairPal.
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