Diagnostic Aids
WARNING: This page is about a different car, the 2003 Pontiac Grand Prix, 2003 Chevrolet Malibu, and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
- If any sensor using a 5-volt bias voltage, such as the Intake Air Temperature (IAT) sensor or fuel level sensor, is shorted to voltage, DTC P1635 may set in addition to DTC P1639.
- For intermittent conditions, Go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.1L CENTURY, GRAND PRIX & MALIBU article.