What it means
The control module detects a high signal in the control circuit for alternative-fuel tank shutoff valve A. The cause may be a short to voltage or another circuit fault.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Alternative-fuel tank shutoff valve A uses a control circuit to operate the valve and isolate the tank when required. The control module sets this code when it detects a higher-than-expected signal in that circuit, which can happen if the wire is shorted to battery voltage or another circuit fault is present.
Common causes
Most likely first.
- Short to B+
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light on
- Alternative-fuel system warning
- Reduced or unavailable alternative-fuel operation
How to diagnose it
- Check freeze-frame data and related alternative-fuel codes to determine when the high signal at valve A was detected.
- Inspect valve A’s connector and harness for pinched wiring, damaged insulation, corrosion, or contact with a power source.
- Follow the wiring diagram to check the valve A control wire for a short to voltage before testing or replacing the valve.
- Check the connector terminals and circuit resistance for poor contact, using the manufacturer’s procedure.
- If no wiring fault is found, test valve A and its control module circuit according to the manufacturer’s procedure.
Common fixes
- Repair a control wire that is pinched against a battery-positive source.
- Clean corroded valve A terminals and secure the connector.
- Repair damaged insulation or replace the affected harness section.
- Replace valve A or repair its control module circuit only if testing confirms the fault there.
Can I keep driving?
The vehicle may remain usable on another fuel, but the alternative-fuel system may be reduced or unavailable. Avoid relying on valve A to shut off the tank until the high signal fault is repaired.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.