1997 Ram 1500 5.9L No Asd Relay Command

Andrew Owner/Technician New Jersey Posted   Latest  
Unsolved
Driveability
Electrical
1997 Dodge Ram 1500 Laramie 5.9L (Z) 4-spd (42RE) — 3B7HF13Z1VG741679
Crank / No Start

Hi guys could use a little help here. this rams pcm wont ground the asd relay control circuit in koeo or cranking. pcm has good powers and grounds and 5 volt ref. scantool does communicate, no codes and i can command asd activation through atm tests. the customer has a what seems to be a new or reman pcm installed on the vehicle. where would i go next? what would prevent the pcm from grounding the asd relay control circuit? TIA

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Boyd Technical Support Specialist
Georgia
Boyd
 

While watching your scan tool spin it over for 10 to 15 seconds and see if the cam and crank will sync. If you can command it you know the circuit is good so it has to be seeing something it doesn't like. Cycle the key on and off three times and leave it in the on position on the third cycle. Watch the odometer window and see if any of the other controllers have codes.

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Dan Owner/Technician
Texas
Dan
 

… Boyd…it is my understanding that the 3 key cycle trick only reports ECM codes (PO anythings)…not with ABS, Airbag, HVAC ,infotainment, TPMS, transmission, stability control , parking assist , ect… just sayin' …Dan H.

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Boyd Technical Support Specialist
Georgia
Boyd
 

I have a 96 trash truck (1500) and it cycles through controllers. (There aren't many)

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Gary Owner/Technician
Colorado
Gary
   

Andrew, if the scan tool's ATM actuates the ASD relay, then the PCM isn't seeing a key-on or cranking signal. The ASD should activate for roughly three seconds after key-on, then deactivate until another key-off, key-on cycle occurs. The ASD should also activate during cranking because it supplies current to the fuel injection and ignition systems. So I'd be looking at the key-on and cranking…

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Agree
Glenn Owner/Technician
Texas
Glenn
 

Hi Andrew, I'm with Gary on this one. Remove the column covers and look at the ignition switch to check for hot spots and a melted area. These switches were bad about that.

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Agree
Timothy Owner/Technician
Wisconsin
Timothy
 

ATM tests can fool you. I know it's happened to me. This is a bad PCM. The ASD should turn on for two seconds, and then only activate when it sees a valid crank signal. Has nothing to do with ‘synch'. You can unplug the CMP sensor on this old pig, and it will still run most of the time. You can manually ground the blue/yellow wire at the PCM and see if it'll run. If you can, then there's…

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Jesse Engineer
Missouri
Jesse
 

As others have stated, when you first turn the key on the ASD should trigger to prime the fuel pump. After that, it requires crank sensor signal to turn on, controlled by the PCM. You can pull the crank sensor and turn the key on. Place an index card across the end of the sensor. Wave or slide a screwdriver blade back and forth across the sensor. This will/should trigger the ASD to turn on. If…

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Justin Technician
California
Justin
 

If I recall correctly a DRB scan tool would allow you to view ASD command state . That would be good to know because if it’s being commanded on without ATM testing when viewing you can look past pcm inputs .

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