DTC 51

Wiring Diagram for Code 51 - PROM Problem:

CODE 51 - PROM PROBLEM

Circuit Description:

Code 51 sets if any one of the following occur:

^ Faulty PROM unit

^ PROM unit improperly installed (may not set a code if installed backwards)

^ Some PROM pins not making contact (i.e., bent).

Always check to see that the PROM pins are not bent and are inserted properly into the ECM, Make certain the PROM is installed in the proper direction as shown in the chart.


Test Description:

Check that all pins are fully inserted in the socket. If OK, replace PROM and recheck. If condition is not corrected, replace ECM. See Chart C-1.

Wiring Diagram for Code 51 - PROM Problem:

Remove or Disconnect


1. Connectors from ECM


2. ECM mounting hardware


Important!


ELECTRONIC CONTROL MODULE (ECM) MOUNTING HARDWARE NOT ILLUSTRATED. HARDWARE CONFIGURATION WILL VARY WITH CAR DIVISION.


3. ECM from passenger compartment

4. ECM access cover

5. PROM


CAUTION: THE IGNITION SHOULD ALWAYS BE OFF WHEN INSTALLING OR REMOVING THE ECM CONNECTORS


Important!


Using the rocker-type PROM removal tool, engage one end of the PROM carrier with the hook end of the tool. Press on the vertical bar end of the tool and rock the engaged end of the PROM carrier up as far as possible. Engage the opposite end of the PROM carrier in the same manner and rock this end up as far as possible. Repeat this process until the PROM carrier and PROM are free of the PROM socket. The PROM carrier with PROM in it should lift off of the PROM socket easily. PROM carrier should only be removed by using the pictured PROM removal tool. Other methods could cause damage to the PROM or PROM socket.


Important!


REPLACEMENT ELECTRONIC CONTROL MODULE (ECM) IS SUPPLIED WITHOUT AN ENGINE CALIBRATION UNIT (PROM) SO CARE SHOULD BE TAKEN WHEN REMOVING THE PROM AS IT WILL BE REUSED IN THE NEW ECM IF THE ORIGINAL ECM IS FOUND TO BE DEFECTIVE.