What it means
Voltage on the fuel mode indicator lamp control line is below the expected window. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
How it works
The control module switches the fuel mode indicator lamp circuit to show the selected fuel mode and monitors the control line. This code sets when the line voltage is below its expected range, commonly because the wire is grounded or the lamp driver is shorted.
Common causes
Most likely first.
- Control wire shorted to ground
- Bulb driver internally shorted
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light may be on
- Fuel mode indicator may be dim or inoperative
- Driver may not be able to tell which fuel mode is selected
How to diagnose it
- Use a scan tool to check the stored and pending codes and observe fuel mode status and lamp command data, if available.
- Confirm which fuel mode is selected and check whether the indicator is dim or completely off.
- Inspect the indicator, its connector, and the control wiring for a short to ground, corrosion, moisture, or damaged terminals.
- Use the wiring diagram to check the lamp circuit for continuity and an unintended path to ground, following the manufacturer's test procedure.
- If the wiring and connections pass, test the indicator driver and module output as specified by the manufacturer.
Common fixes
- Repair a control wire that is shorted to ground.
- Clean or repair corroded or loose terminals in the indicator circuit.
- Replace a failed indicator lamp or assembly if it is the cause of the low circuit reading.
- Repair or replace the lamp driver or control module if testing confirms an internal short.
Can I keep driving?
The fault may leave you unable to tell which fuel mode is selected. Verify the mode using the vehicle’s normal controls and avoid relying on the indicator until it works.
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.