Code 452, VSS issue?

Hi,

Is this the only code present? As far as the code, it indicates there is an error in the programable speed/odometer module. Because this can be caused by a few different things, we need to work through a few tests.

The problem is my manual provides one procedure and then based on the outcome; it sends me to the next.

Do me a favor. Take a look at the first step below and let me know if you are comfortable performing it. If you are and complete it, let me know the results.

Take care and let me know what you find.

Joe

See pics below.

Thank you for replying,
I do not have a breakout box; can this be measured from pins 3&6 on the PCM connector?
I should have mentioned in my request for help that I have a spare PCM (cardon reman) and have tried that with no change.

Checked at PCM connector with one auto ranging and one set at 20k.

I attached the next two steps because the outcome can either require more testing or it can be an open circuit that needs to be repaired.

Let me know.

Joe

Thank you. I won't be able to get to this test until Friday.

Hi,

Thanks for letting me know. If possible, let me know over the weekend.

Take care,

Joe

It has been raining most of the weekend here in Central Florida, won't be able to get to that test till the 23rd.

Hi,

No problem. When you get the chance, let me know. I'm interested in knowing what you find.

Take care and if I don't hear from you, have a nice Thanksgiving.

Joe

Thank you, Joe, for being patient with me, continuity and short to ground pin check is good.
PCM 3 to PSOM 5= 0.3ohm
PCM 6 to PSOM 7= 0.4ohm
PCM 3 to PCM (6,37,40) OL
I have included the connector pinout I have been using with this test.

Hi,

Based on the results, we have a short. The manual is suggesting that everything be reconnected and then rerun the quick test.

Starting with pic 2 is where it goes next. Let me know what you find.

Let me know what you find or if you have other questions.

Joe

See pics below.

At what step determined a short. I would like to recheck that step before I continue. I thought my results would lead to test DS4, checking the RABS module .

Hi,

checking for a short to power or ground was done in the first portion of the diagnostics. I reattached it below.

Let me know if this helps.

Take care,

Joe

See pic below.

I believe I must have miscommunicated my reply. When checking from pin 3 to Pin 6, 37 and 40 I gave you an answer of OL. I meant open loop for no continuity between any pins. That would be yes all above 10,000 ohms.

Hi,

No problem whatsoever. If that is the case, we need to jump to DS 4. Take a look through the diagnostics. I have a feeling this is going to be an easy one for you.

Let me know.

Take care,

Joe

See pic below.

Yes, resistance check is good.

Hi,

Let's move on to DS 5. I attached it below. Let me know the results or if you have questions.

Take care,

Joe

No AC signal between pins 3 and 6.

Hi,

I was ready to move to an instrument cluster test, but I think we found the issue. Take a look through the technical service bulletin I attached below. You indicated the sweeping in the speedo.

Let me know your thoughts.

Take care,

Joe

See pics below.

Yes, I agree the PSOM needs repair. There is an AC signal on pin 4 from the VSS but no output on pin 5 to the PCM. I only got 2.9 volts on pin 4, is that adequate voltage? If not do you have a check for the servo amplifier or the ABS module to determine what is pulling the signal down.
Thanks again for all your help and Happy Holidays.

Hi,

Take a voltmeter and check the signal return voltage to ground. Let me know what you find. Also, check pin 4 voltage to ground.

Pin 4 should be around 5v. If you ground the return voltage (pin 5) to a known good ground, it may indicate a return. If it does, the PSOM may be faulty.

Joe

Sent the PSOM to Texas Speedometers for repair. Got it back in just over a week. No codes, no flashing stalk light, all is right with the world again. Thanks again for all your help.

Hi,

Thank you for the update. I'm glad to know you got it fixed.

Please feel free to come back anytime in the future if you have questions. You are always welcome here.

Take good care of yourself.

Joe