ECM Check for code 54 (fuel pump relay)
Thread Starter
Pro
Joined: Apr 2001
Posts: 539
Likes: 4
From: Rochester, NY
ECM Check for code 54 (fuel pump relay)
I've been trying to diagnose a code 54 I've been getting when the car has not
been started for over 4 hours (starts fine if started under 4 hours). Both the
fuel pump and fuel pump relay are in working order. How can I confirm that
the ECM is not the root cause of this very frustrating code 54 issue ?? Any help on this is greatly appreciated!
been started for over 4 hours (starts fine if started under 4 hours). Both the
fuel pump and fuel pump relay are in working order. How can I confirm that
the ECM is not the root cause of this very frustrating code 54 issue ?? Any help on this is greatly appreciated!
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Re: ECM Check for code 54 (csc67)
Backprobe the ECM fuel pump voltage circuit - Pin B2 Red - with a test light to ground or a DVM. Test light should come on for 2 seconds with ignition on or there should be battery voltage for 2 seconds. If not, the circuit is open. If the test light lights or you have voltage, it's the connector or the ECM.
Le Mans Master
Joined: Jul 2001
Posts: 5,297
Likes: 0
From: Stamford VT
Re: ECM Check for code 54 (SunCr)
I would stick to the digital multimeter, not the test light. The test light draws enough current to blow the output transistor in the ECM. So does the heating element of a heated oxygen sensor. Ask me how I know.
If it's not the relay and it's not the pump, all it leaves is wiring or the ECM. If you do a continuity check on the wiring, that leaves the ECM.
I've got the actual flow charts for this procedure in my repair manual. I followed them when troubleshooting mine, and it correctly led me to the ECM that I managed to fry.
On the TPI cars, the ECM wire on the fuel pump relay is the small green wire with the black stripe. Maybe it was red on the LT1 cars... I really have no idea.
If it's not the relay and it's not the pump, all it leaves is wiring or the ECM. If you do a continuity check on the wiring, that leaves the ECM.
I've got the actual flow charts for this procedure in my repair manual. I followed them when troubleshooting mine, and it correctly led me to the ECM that I managed to fry.
On the TPI cars, the ECM wire on the fuel pump relay is the small green wire with the black stripe. Maybe it was red on the LT1 cars... I really have no idea.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Re: ECM Check for code 54 (Jim85IROC)
It's not the output or driver circuit (dk grn) that monitors the FP voltage. Red is from the Relay & a battery voltage signal to the ECM. Code 54 means there was less than 2 volts on this circuit for 1.5 seconds since the last reference pulse. You could check it at the Relay, Pin E, but that doesn't mean it's getting to the ECM.
