Intermittent Diagnosis Guidelines

An understanding of code storage and automatic code erasure is important. First, codes can only be stored if the anti-lock electronic control unit has power. The anti-lock electronic control unit gets primary power from the ignition feed into Pins 1 and 9. If this voltage is missing or less than 11V, the anti-lock electronic control unit will not initialize and therefore, a code cannot be stored. However, any code already in memory will be retained as long as the Keep Alive Memory power is available. Code 16 (system OK) is present whenever the anti-lock electronic control unit sees the required voltage (assuming no other diagnostic trouble codes are present).

Therefore, some codes read out in the System Pre-Check may not result in any trouble found in the pinpoint test performed. Most likely, this is an indication of an intermittent electrical concern.

To minimize mis-diagnosis, refer to the intermittent diagnosis procedure if no resolution has been reached by the end of a particular pinpoint test.