Trouble Codes

C-4 diagnostic system is programmed to flash a series of codes through the "CHECK ENGINE" light. After light becomes activated by the system, it is necessary to ground a Trouble Code test lead, with engine running, so system can flash proper Trouble Code. See Figurefor location of Trouble Code test leads. 

When "CHECK ENGINE" light comes on, trouble in C-4 system is indicated. A series of codes are programmed to assist in diagnosis and correction of the problem. See "C-4 System Diagnostic Trouble Codes" table for explanation of codes. 

Codes are flashed by "CHECK ENGINE" light after the trouble code test lead is grounded. Codes will be flashed as follows: light will flash 1, 2, 4 or 5 times to indicate first number of code; then, it will flash (after a short pause) 1, 2, 3, 4 or 5 more times to indicate second number of code. After a long pause, signal will repeat itself two more times.

FOR EXAMPLE - With Trouble Code lead grounded and engine running, if problem is a Shorted Coolant Sensor Circuit, Code 14, light will flash one time, pause, then flash four times. A long pause, then repeat one-and-four flashes, a long pause and repeat again. 

If more than one trouble spot is detected, one code series will flash, then the other code series will flash.