OK, I have an original owner 1995 Nissan Maxima; 241k on car; around 50k on engine. Runs like a dream, gets 29.5 MPG @ 70 MPH, and has a lot of years left. However recently my idle started climbing to 1500-1800 RPM whenever vehicle is placed in gear (or if steering wheel is turned) at a dead stop, or if vehicle is rolling at all (in gear or not). It also has a “dead spot” under full acceleration at right around 3800-4000 RPM. IACV, MAP, TPS, Knock, etc etc all new, yet it continues to throw a PO120 (TPS) code. I just took it to a dealer who told me that I have a broken/shorted wire to my TPS inside the harness, and that he has NEVER had any luck repairing them. He gave me service bulletin NTB98-008b, which addresses the 4th generation's tendency to get broken wires in the harness, and right in that bulletin it outlines the repair procedure. He is recommending a new $3300 repair ($2200/harness, $1100/labor), as he says they have NEVER had any luck with wire repairs of that nature. Seems to be a load of bull; has anyone out there ever repaired one successfully? Thx

 

This is quite true actually, In order to find where the wire is broken or shorted would require them to unwrap the whole harness. Sure they may be able to fix that one connection but with how fragile those harnesses are, another wire could potentially break or short in the process. We have gotten a couple 4th gens in with harness issues and we haven't put a harness in any of them, once the customers see the price they either just deal with the issue or trade the car in lol.

My advice- Deal with the idle issue or go to a junk yard and pick up a engine harness for $15 and hope it doesn't have any bad connections or shorts.

 

What does the harness cost new from courtesy or the bay?

 

Have considered that, except the service bulletin oulines in great detail the repair process. The idle is a pain in the butt that I could live with, but the real problem is not being able to pass emissions with the CEL light on......

 

Havent been able to locate one on ebay. Nissan wants $2200 (ouch).....

 

Run your own shielded wire from the TPS to the ecu harness. Find a shielded rca cable or something and cut off the ends.

 

If you wanna fix it on the cheap get a phone line cable or cat5 and bypass the OEM harness straight to the ecm.

 

Lol we were thinking the same.

 

That might be too small gauge but u get the idea. This was the dealership fix on TDI VWs for the glow plug harness.

 

Def. not worth it to buy a new harness. Like others have said, if you feel confident enough in your wiring skills then bypass your harness completely. Its not a tough fix, just depends on which route you want to take.

 

Like others have said, run a completely new wire. TPS signals are not as sensitive as other signals, such as O2 or speed sensor signals. You should be fine running new wires.

On a side note, that seems very high in price.

 

Thx, you guys. Thats exactly what I was thinking, but what I am confused about is why didnt the dealer suggest that (new wire), or a splice? Wondering if its a liability issue with a repair "ouside the box"?

On another note, how do you find the same wire where it connects to the ECU plug? Through the color code? And, do I cut/splice the wire or do I have to figure out how to get it into the connector itself?

 

They don't make any $$$ on that job.
The dealer want's to sell parts and install them.
That's how they make $$$.

Download a copy of the FSM for the wire layout to your ECU.

 

yo man.... dealers jus out to screw u.

Like NJ sd, they dont make money on easy fixes. Running wire is an easy fix. Jus run your own wire and solder the connections at the harness. After u confirmed it works, wrap it with plastic wire protection.

All u really need is a copy of FSM.

i wonder if the dealer even ohm'd the wire for a short. Do that first, confirm the wire is shorted.

 

Yes, he ohmed it and said that is was shorted, not broken. That's why he suggested the new harness, claiming that it indicated there were probably other probs inside of the harness. So I guess what you guys are saying is I just locate the same color-coded wires on both the ECU and tps connector sides, cut them off after about an inch or two, and splice in new shielded wire (ie maintaining the wire that's connected at the connector terminals)?

 

Exactly.

jus cut an inch or so at each harness and run new wire. Determine which wire is bad too. there are a few for the TPS.

 

Assuming its safer to replace all 3?

 

https://docs.google.com/viewer?a=v&p...zM2Rk&hl=en_US

and

https://docs.google.com/viewer?a=v&p...xYWMx&hl=en_US

There you go. Should get you along.

 

Awesome; thx much.... :-)

 

My friend had the same issue with his ES300, sudden jump in rpm when wheel is turned in park and slow pick up when flooring it, but as far as fixing it, it wasn't as extensive as yours. I say just to be sure and on the safe side have your tps connection checked if you havent done so already just to be sure. Nissan might be thiniking your coming back so that they can fix the problem lol

 

. . . SN: If you guys keep this up Nissan Techs will soon be out of jobs lmao Maxima.org

 

I actually had ohmed all the wires myself, but wanted to be sure by taking it in to the dealer. $133 wasnt too bad to confirm what I already suspected. I havent decided yet if I will splice in new wires (which scares me with ECU's), or replace the harness with a good used one. I DEFINITELY am not going to pay $2200 for a new harness from Nissan..... :-)

 

BTW, my flat spot is only at absolute full throttle when the engine is torquing to the max. Back off just a bit, and I'm flying like a raped ape (like all 4th gen Maxima's should.... :-) ).

 

I have the same problem, but i replaced the harness and the sensor and still have the same problem. I hooked a scanner to the car and im getting a non linear reading from the tps. After more investigation I found that the sensor ground is contaminated. 5v can be tested from sensor ground to chassis ground. According to the wiring diagram that ground is shared with some other emissions related sensors and solenoids. I'm assuming that the primary coil has failed in one of the solenoids and is back feeding the ground. I'm planning to schedule an appointment with an auto electrician to help me sort this out.

 

OK, I just took the insulation of the wires leading to the TPS and found that the grey insulation & metal shielding on the white wire are stripped back about three to 4 inches after the connector. I am wondering if that is what could be causing MY problem here (rather than a broken wire further back in the harness, as diagnosed by the Nissan dealer)? If so, how do you just replace the shielding for that 3" section? I am assuming a splice wouldnt be as copasetic......

 

BTW, when you say "sensor ground", are you referencing the TPS connector? ie there are 3 wires; a red 1, a white1 w/metal shielding & grey insulation, and a black one. Do you mean the black wire? Because that one is leading into the harness, and I dont see how it could be grounded from there....

 

BTW, killer Max. Mine is black/blacked out similar to yours; just sans the turbopopper......:-)

 

Thanks, Mine is actually dark green. It was the black wire on the sensor socket. If you use a volt meter you get 5 volts from the black wire to ground on mine. I'll let you know when i figure out the cause.