P0600
Serial Communication Link
When a vehicle powertrain module registers the fault code P0600, it points directly to an internal system malfunction identified as "Serial Communication Link". Operating your engine under this condition may degrade long-term fuel maps.
Driver's Summary
Storing code P0600 is your car's way of telling you something is wrong with the serial communication link. The most common signs are multiple warning lights on dash, transmission in limp mode, no start condition. Stop driving as soon as it is safe to do so. This fault can lead to expensive secondary damage if left unaddressed.
Symptoms
Multiple warning lights on dash, transmission in limp mode, no start condition
Common Causes
- Dead battery
- Corroded CAN bus connectors
- Failed control module (PCM, ABS, TCM)
- Short circuit in CAN wiring
How to Fix
- 1 Load test battery
- 2 Inspect and clean module connectors
- 3 Perform network scan to isolate dead module
- 4 Repair shorted CAN bus wiring
Technical Explanation
P0600 is stored after the control module confirms the fault over multiple ignition cycles, ruling out transient electrical noise as the cause. The PCM distinguishes between electrical faults (circuit codes) and performance faults (rationality codes) by comparing the sensor's reported value against what other sensors would predict under the same engine operating conditions. After two failed drive cycles, the code transitions from a pending to a confirmed DTC, and the PCM activates the MIL. Clearing the code without repairing the fault will result in re-illumination within one to two complete drive cycles.
Is It Safe to Drive?
This fault carries real mechanical risk. The root causes — including dead battery — can trigger a chain reaction of component failures if the vehicle continues to be driven. Have it towed or drive directly to a shop without delay.
Mechanic's Pro Tip
Before replacing any component on P0600, spend 5 minutes inspecting the wiring harness and connector first — corrosion, chafed insulation, and backed-out pins cause the majority of these faults and cost nothing to fix. Use a multimeter to measure voltage drop across the connector pins under load; anything above 0.1V indicates excessive resistance that will cause intermittent failures even after replacing the sensor.
Diagnostics and wiring repair: $150 - $400; Module replacement: $500 - $1,500+