New here: Temp gauge failure

stevejg said:

Well heres the weird thing...I had to have my original BeCM swapped to a junkyard unit which surely had higher mileage. Upon installation, the cluster still reads the correct mileage, however it says "odometer error" every time I start the car.

Are you saying that even though the BeCM has been swapped to a unit with higher mileage, swapping the cluster to a higher mileage unit to check and then swapping back in the original will force the BeCM to adopt the mileage of the second unit?

Just odd considering it doesn't do that now...

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As Fanatic says above, there is a magic trick.... No doubt some diagnostics can solve that issue....not sure how the US market systems are setup, but the UK market does adopt the higher mileage reading unless magicked!!

stevejg said:

I have not tried that. I apologize, but let me re-phrase that...do you mean disconnect the coolant sensor plug, and jumper the wires-use a paperclip or something to cross all four of the lines?

As far as the replacement BeCM...interesting theory. However the replacement has been in the car a couple of months now and this problem only surfaced last week

AND THANK YOU TO EVERYONE HERE THIS INFO IS INVALUABLE!!

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Just jumper the two connectors inside the plug which normally connects to the sensor

rodntod said:

Just jumper the two connectors inside the plug which normally connects to the sensor

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Ok I'll certainly try that. I did not install the sensor, I had the shop do that but after watching them I'm confident to do it myself. I did notice though that my sensor had four prongs on it...though I did not get a chance to inspect the wiring perhaps it is only two lines.

Saint.V8 said:

As Fanatic says above, there is a magic trick.... No doubt some diagnostics can solve that issue....not sure how the US market systems are setup, but the UK market does adopt the higher mileage reading unless magicked!!

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Unless you have the kit to interfere with the flash memory in the instrument cluster it cannot easily be re-set, even then a re-set to zero is the easiest option. The BECM is a different ball game, not sure if it can be done with the Faultmate SM035 module.
The odometer error message is normal if there is a difference in mileage readings between the BECM and the instrument cluster, eventually it will update to the highest mileage figure I believe.

Pulled the connector off for the sensor..seemed really easy to do like it wasn't snapped in, so I re connected it, no luck

Since it is four prongs, how would I go about jumpering them?

Two by two or four at once/etc

That won't short anything out?

Had another thought and not sure if it's related...I have NEVER heard the aux fans come on...

Just chipping in here, but could this be a simple thermostat failure (stuck open) after the overtemp?
I have had a similar issue and I measured the output from the temp sensor and compared it to the temp co-efficient for the device, it seemed to be working ok but low for an engine that had been runing an 30-40 mins.

JamesBB said:

Just chipping in here, but could this be a simple thermostat failure (stuck open) after the overtemp?
I have had a similar issue and I measured the output from the temp sensor and compared it to the temp co-efficient for the device, it seemed to be working ok but low for an engine that had been runing an 30-40 mins.

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I don't believe so because I was able to plug in a handheld code reader that gave live data, and it showed my temp at 93-98C

stevejg said:

Had another thought and not sure if it's related...I have NEVER heard the aux fans come on...

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The aux fans are not connected to your problem, they operate normally with the aircon and only with a serious overheat do they operate to act as engine cooling.
You need to look at RAVE to see which pins to short.

UPDATE: STUMPED!

Soo. the shop has checked all wiring. Everything is perfect. Lines from coolant sensor go first into engine ECU, then from Engine ECU to BECM then out to gauge. So far, they have swapped and re-coded engine ECU as well as BECM to no avail. Also swapped instrument clusters. No luck.

Should also mention coolant sensors have been swapped twice now.

Here's the thing...they can successfully drive the gauge from diagnostics. We are all absolutely stumped.

stevejg said:

UPDATE: STUMPED!

Soo. the shop has checked all wiring. Everything is perfect. Lines from coolant sensor go first into engine ECU, then from Engine ECU to BECM then out to gauge. So far, they have swapped and re-coded engine ECU as well as BECM to no avail. Also swapped instrument clusters. No luck.

Should also mention coolant sensors have been swapped twice now.

Here's the thing...they can successfully drive the gauge from diagnostics. We are all absolutely stumped.

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This is exactly where i was.
What are the part numbers of the sensors that have been fitted?

rodntod said:

This is exactly where i was.
What are the part numbers of the sensors that have been fitted?

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Well that's a good question, I'm not sure the shop is closed now...they both came from Atlantic British, a major parts provider here in the States.

They only list one sensor for my specific truck on the website so I imagine if they had the wrong sensor listed I wouldn't be the only one with this problem.

Is the radiator temperature sensor worth checking in to? Could a fault here disable or otherwise tamper with the temperature gauge?

stevejg said:

Is the radiator temperature sensor worth checking in to? Could a fault here disable or otherwise tamper with the temperature gauge?

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What Radiator Temperature Sensor?

Sounds like a classic case of wrong sensor to me.

This should be the required Sensor for Vin No's XA410482 onwards.....


This is the older one....

MEK 100160 is the one that was installed

Hi guys...this will be the final update before I install a digital temp gauge. So far, the shop has changed out the cluster, ECM, BECM, and tested all wiring. Everything was swapped from a truck that runs and is driven daily. All wiring measures out, and the most frustrating thing is that we are getting the correct reading at the harness that plugs into the cluster...the end result...not only is that resistance correct, it matches the resistance we are getting from the daily driven truck. If I take my cluster and swap it into the other truck, it functions perfectly.

But my gauge will work and go to the center when plugged into diagnostics. I and the shop are out of options:mad2:

Have you thought of scoping the temp gauge wire?

fanatic said:

Have you thought of scoping the temp gauge wire?

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What do you mean by scoping? I know they have followed the wires from the coolant sensor to the ECM then to BECM and up to dash, and all the wires checked out good, including grounds. The wires to the dash are actually two power wires, and the ground must be in the harness somewhere. Kind of strange. Also we have checked for correct alternator/battery voltage, it was ok.