OBD codes / P0600
P0600
ModerateSerial Communication Link Malfunction
Drivability with P0600 ranges from 'seems fine' to intermittent stalling, because the computers can lose track of each other mid-drive. Treat it as a prompt-diagnosis code rather than an emergency — but don't set out on a long trip with it, and get the battery, grounds, and wiring checked before anyone suggests replacing a computer.
What this code means
P0600 means the engine computer detected a fault on its data communication link with other modules — the messages it expects from the rest of the car aren't arriving correctly. It's less an 'engine problem' and more a wiring-and-electronics problem: damaged or corroded connectors on the data lines, a poor power or ground connection at a module, or a failing module dragging the link down. Low or unstable battery voltage can also trigger it, so checking the battery, charging voltage, and ground straps is the cheap and correct first step. Disconnecting the battery for a few minutes (a hard reset) sometimes clears a one-off glitch — if the code returns, the circuit needs real diagnosis. Module or ECM replacement is the deep end, reached only after wiring, power, and grounds check out.
Symptoms you might notice
- Check-engine light, often with other codes from multiple systems
- Gauges or warning lights behaving erratically
- Intermittent stalling or hard starting
- Scan tool has trouble talking to the vehicle
What it costs to fix
Varies by vehicle — get it diagnosed.
The repair cost for this code depends too much on your exact vehicle and the underlying cause to quote a meaningful range. Confirm the cause first so you only pay for the fix you actually need.
Diagnose P0600 for my vehicle →Frequently asked
Can I drive with P0600?
Cautiously, for short trips. Communication faults can be intermittent and can cause stalling or erratic behavior without warning. Have it diagnosed soon rather than living with it.
Does P0600 mean my ECM is bad?
Usually not. Wiring damage, corroded connectors, poor grounds, and low battery voltage are far more common causes and much cheaper to fix. The module itself is only condemned after those check out.
Will disconnecting the battery fix P0600?
It can clear a one-time glitch — disconnect for several minutes, reconnect, and see if the code returns. If it comes back, there's a real fault on the communication circuit that needs diagnosis, not another reset.
Why does a weak battery cause communication codes?
The car's computers need stable voltage to send and receive data correctly. When voltage sags — from a tired battery, bad grounds, or a weak alternator — modules drop off the network and communication codes appear. Always verify voltage first.
Seeing P0600 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0600 for my vehicleRelated trouble codes
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Generic OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.