Testing PCM (No crank)

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runs_with_waves

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Good morning everyone!

First time poster here. Loving this resource so far. Greatly appreciate the service manuals.

I have a No Crank condition.

So far, I have; Ignition Cylinder (Replaced), Ignition Switch (Replaced), Neutral Safety Switch (Bench Test - good), Starter Relay (Bench Test - Good), Starter Solenoid / Motor (Bench Test - Good), Power Dist. Relay (Replaced).

After digging through the Service Manual I have a nice list of 5v circuits to test (oh, joy!) that could cause the PCM to trip the ASD (not getting any signal to the ASD from the PCM), or just not function. I didn't find a testing procedure for the PCM itself in the service manual, so either I missed it in the 1678 pages, or it's not in there.

My initial search had me testing the Ignition Sense, and I was able to confirm 12v from the Neutral Safety Switch to the PCM (C3, Pin 21), but I am not getting enough Voltage out of C3 Pin 38 to close the Starter Relay circuit (Getting 31.5mV's w/ Key On and Key Start, 0.0v at Key Off, and 0.2 Ohms between Pin 38 and Relay).

Tonight I am going to test Ignition Switch to the PCM.

Any insight or direction would be greatly appreciated.

o7
 
If I remember correctly, the PCM on the 05 and 06 is involved in the actual cranking.

Did you verify the ignition actuator pin is good?

Mark @Wranglerfix is the person to contact if you narrow it down to the PCM.
 
JKP said:
If I remember correctly, the PCM on the 05 and 06 is involved in the actual cranking.

Did you verify the ignition actuator pin is good?

Mark @Wranglerfix is the person to contact if you narrow it down to the PCM.
Click to expand...

I disassembled the ignition while installing Ignition Switch, pin was not broken. And the ignition switch appears to function, as all obvious peripherals power up with the key in the Run position.

Going to be testing Ignition Switch outputs to the PCM tonight, if I have daylight after work.
 
runs_with_waves said:
Good morning everyone!

First time poster here. Loving this resource so far. Greatly appreciate the service manuals.

I have a No Crank condition.

So far, I have; Ignition Cylinder (Replaced), Ignition Switch (Replaced), Neutral Safety Switch (Bench Test - good), Starter Relay (Bench Test - Good), Starter Solenoid / Motor (Bench Test - Good), Power Dist. Relay (Replaced).

After digging through the Service Manual I have a nice list of 5v circuits to test (oh, joy!) that could cause the PCM to trip the ASD (not getting any signal to the ASD from the PCM), or just not function. I didn't find a testing procedure for the PCM itself in the service manual, so either I missed it in the 1678 pages, or it's not in there.

My initial search had me testing the Ignition Sense, and I was able to confirm 12v from the Neutral Safety Switch to the PCM (C3, Pin 21), but I am not getting enough Voltage out of C3 Pin 38 to close the Starter Relay circuit (Getting 31.5mV's w/ Key On and Key Start, 0.0v at Key Off, and 0.2 Ohms between Pin 38 and Relay).

Tonight I am going to test Ignition Switch to the PCM.

Any insight or direction would be greatly appreciated.

o7
Click to expand...

Should also be noted that no DTC (error codes) were displayed prior to, during or after testing.
 
[Update] I was able to confirm Ground at Pin 38 on C3 with the key in the run position.

My next curiosity was continuity between the Ignition Switch and Starter Relay. Resistance was 14ohms, more than I would like to see. I believe these 14 ohms and the 75 at the relay may be enough to keep the relay from activating.

Tonight I will be doing some more trouble shooting around the harness plug for the ignition switch looking for low/no voltage.
 
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