Key On, Engine Off Test & Code Descriptions
PROCEDURE1. Turn key off, then turn it on again without turning on the engine. Observe and record codes and then proceed to the appropriate steps as indicated below:
NOTE: Ignore any initial pulse surges that may occur immediately after turning the key on. The output codes will appear after 5 seconds.
a. Code 11-Continue to Engine Running Functional Test except in cases where vehicle may have been modified for operation at high altitudes, as noted in Step e., "Code 65".
b. Code 51-Continue to Test 3, "Open Switch" under Subroutines.
c. Code 52, 53, 56-Continue to Test 8, "Vacuum Switches".
d. Code 62-Continue to Test 4, "Wide Open Throttle Vacuum Switch".
e. Code 65 On vehicles with altitude service fix (pin 18 of MCU module connected to engine block ground), a service code of 11 may indicate a failure code, and 65 may indicate a pass condition. Continue to Test 7, "Altitude Input" under Subroutines. This modification is not intended for use on vehicles operated primarily at locales under 3100 ft. above sea level.
f. Steady high or low voltage-Continue to Test 16, "No Self Test Output" under Subroutines.
g. Erroneous Codes-Continue to Test 16, "No Self Test Output" under Subroutines.