P0683 code meaning
Glow Plug Control Module 1 to PCM Communication Circuit
Powertrain system Generic code P06xx codes Check engine light
What P0683 means
Glow plug module 1 reports to the engine module over a feedback wire (Bosch-type systems expect it inverse to the activation line) or the bus; GM and Ford report a lost bus link as U0106, Saab as P0380/P1380, and no manufacturer document available to us uses P0683/P0684 themselves. P0683 means communication or feedback from the glow module to the engine module is missing or the line is open or shorted. The engine module then no longer receives plug status reports, so the individual plug monitoring fails; depending on design the glow module keeps glowing on its own timing or not at all. The activation line in the other direction is P0670/P0383/P0384.
P0683 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P0683
- Check engine light (glow plug lamp may flash or stay on)
- Harder cold start, long cranking in frost
- Rough running and white smoke after a cold start
- No individual plug reports any more
Common causes of P0683
- Most likelyCommunication or feedback wire between glow and engine module open, chafed or connector corroded
- PossibleGlow module without supply or ground (fuse, main cable) – does not answer
- PossibleGlow module faulty internally
- Less likelyGlow or engine module software or programming
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Glow plug control moduleGlow plug feedback lineEngine control module
What each part of P0683 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 6 | Area: computer (engine control module) and output circuits. |
| 83 | The exact fault in that area. |
What to do next
- Note P0683 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0683
What does P0683 mean?
P0683 means "Glow Plug Control Module 1 to PCM Communication Circuit". Glow plug module 1 reports to the engine module over a feedback wire (Bosch-type systems expect it inverse to the activation line) or the bus; GM and Ford report a lost bus link as U0106, Saab as P0380/P1380, and no manufacturer document available to us uses P0683/P0684 themselves. It is a generic code, so it means the same on every make.
Is it safe to drive with P0683?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0683 fail an emissions test?
Yes, it can. P0683 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0683 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P0683 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.