[dwightbresemann]

Since all 4 sensors in the rear are effected, or not detected by the PAM, we will focus on one sensor. Fix the one, and all four should be fixed.

Each sensor on the rear bumper have 3 wires. So, one wire will be 5 volts to the sensor. One wire will be less than 5 volts out of the sensor (signal). And one wire will be ground back to the PAM, not chassis, or frame ground.

Set the volt meter to the 10 volt scale. Testing will be at the came connector to the PAM, C4014. We will test the circuit for the outer, driver's side sensor. All tests are KOEO.

Find pin #9 at C4014, it will be a blue wire with a white stripe. This the 5 volts out of the PAM.
Find pin #12 at C4014, it will be a green wire with a white stripe. This ground to the PAM.

Back probe both pins, do you read around 5 volts?

There is no need to test the signal wire. Just power and PAM ground.

 

[bustangadventures]

Checked the signals. My meter only doesnt do 10 volts but i still tested it. Strangely it is reading just a bit lower then the natural battery power of the vehicle.
Car battery was reading 10.6 today and this test was 9.99 so not sure what that means.

 

[dwightbresemann]

It's not recommended to do any type of diagnostic with a battery less than 12 volts. Computers and modules do wacky things with a low battery. Charge the battery, or replace it if more than 3 yrs old.

What circuit did you test to find 9.99 volts? What pins?

The second test was for the voltage 5 volt reference circuit.

 

[bustangadventures]

The 9.99 Volts was for pins 9 and 12. I am not sure how I am getting this reading if it is only supposed to be a 5 Volt circuit. Could the PAM just be completely shot and thus causing this?

 

[dwightbresemann]

Well, I guess anything is possible. At this point, I would remove the connector and inspect for damage, corrosion, water staining.

Disconnect the driver's outer rear sensor. Test again. Also, to verify the meter's accuracy, find a 9 volt and "A"
battery and test their voltages. Quality control.

 

[bustangadventures]

Hi, I charged up the battery and am reading 12.3 for the battery and 11.89 for the pin 9-12 test.
It doesn't look like there is any corrosion or any damage to the PAM.
Is there a second main grounding spot for the car? Maybe on the chassis itself? Could the ground that they are attached to be shorting out on the ground of the chassis? Im not sure if that makes any sense!

 

[dwightbresemann]

The PAM is its own little computer, but we call it module. Yes, the PAM has another power and ground. We test those in the beginning (1st test).

Pin #1 is the power for the PAM. 10 amp fused power. Pin #4 is the ground out of the PAM module (frame or body ground). This ground is G301.

Built within the PAM is an analog to digital converter. This digital processor sends out a low voltage (5 volts) to a sensor. This is Pin #9. The sensor returns a signal back to the processor, which will be less than 5 volts. This Pin #15. Last is the ground. The PAM processor requires it own discreet ground (low noise). This is Pin #12.

So, if are truly getting battery voltage out of pin #9 &12, then yes, the PAM has failed.

 

[bustangadventures]

Ugh, bought a new PAM and installed it. Still not working!!! still a similar reading of over 11 volts!

 

[dwightbresemann]

Did you program the new module?

 

[bustangadventures]

I am unsure what that means, to be honest. I bought it from a scrapyard (They tested it so i know its working) and it came from the same year and make of my escape. How do I program it?

 

[bustangadventures]

@dwightbresemann I noticed my Trailer hookup doesnt seem to be working anymore. It worked before the winter. Could that have anything to do with my current issue? thinking if the ground isn't secure, it would cause both to malfunction?

 

[dwightbresemann]

I'll check the wiring diagram and get back to ya. Since the PAM was from a salvage yard, programming won't be necessary.

 

[bustangadventures]

@dwightbresemann. Glad to hear about the PAM not needing programming. That was way over my head!
I was inspecting all the wires and I found a cut in the Blue and *********** wire just after it comes out of the inside of the car going to all of the sensors. I cut it and tested the power, its only reading at 0.30. I didn't have a clean ground source in sight but used the chassis of the car to ground off of. Any input on this? Is that helpful lol!

 

[dwightbresemann]

Good morning, is the blue wire actually blue with a white stripe? If it is, this is the 5 volt power that feeds all four rear parking sensors. Reading .03 volts may be the test voltage the PAM sends out to check the condition of the circuit.

The 5 volt circuit does NOT use body ground to complete the circuit. The green wire with a white stripe is the return ground to the PAM for the 5 volt circuit.

 

[bustangadventures]

@dwightbresemann, Ok so then if I back probe the Green Wire with White stripe, and the Blue wire with White Stripe then I should be able to get a full 5 volt circuit. Would that be correct?

I was really hoping that by finding that power issue, it would be working but not yet!

 

[dwightbresemann]

Correct