Continuous Memory Failure Diagnostic Trouble Code (DTC) 512

1994 PCED OBDI-A

SECTION 18A: Diesel Diagnosis — 7.3L DI Engine

AH: Continuous Memory Failure Diagnostic Trouble Code (DTC) 512

AH1 CHECK KAPWR TO POWERTRAIN CONTROL MODULE (PCM)

Continuous Memory DTC 512 indicates the PCM has experienced a power interrupt in its Keep Alive Memory (KAM) circuit.

Note: If KAPWR is interrupted to the PCM, for example when installing a breakout box, or when battery is disconnected, DTC 512 may be stored in Continuous Memory.

Key off.
Disconnect powertrain control module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
Install breakout box, leave PCM disconnected.
Measure voltage between Test Pin 55 and Test Pin 51 or 76 at the breakout box.
While observing DVOM, grasp the EEC-IV harness and wiggle, shake or bend a small section while working from the PCM to the dash panel.

Does DVOM indicate less than 10.5 volts?

Yes	No
SERVICE open circuit. REMOVE breakout box. RECONNECT PCM. RERUN Scan Tool Diagnostic Test.	RECONNECT PCM. GO to AH2.

AH2 INSPECT ENGINE COMPARTMENT WIRING FOR PROPER ROUTING

Clear Continuous Memory DTC.
Wait 5 minutes to allow DTC 512 to reset.
Rerun Key On/Engine Off Self-Test.

Is DTC 512 still present on reset?

Yes	No
REPLACE PCM. REMOVE breakout box. RERUN Scan Tool Diagnostic Test.	REMOVE breakout box. RECONNECT PCM. SERVICE other DTCs as necessary. If none, testing is complete.