What Does P2666 Mean?
The PCM has detected voltage on the Fuel Shutoff Valve B control circuit that is lower than expected specifications. This indicates a short to ground or excessive resistance in the circuit preventing proper valve operation.
Common Causes
40%
Short to ground in fuel shutoff valve control circuit wiring
30%
Failed fuel shutoff valve B with internal short to ground
15%
Damaged or pinched wiring harness causing intermittent ground contact
10%
Corroded connector creating high resistance path to ground
5%
PCM internal short circuit in driver output
Diagnostic Steps
1
Step 1: Disconnect fuel shutoff valve B connector and check for voltage short to ground on control wire
2
Step 2: Measure resistance between control wire and chassis ground with valve disconnected (should be infinite)
3
Step 3: Check fuel shutoff valve B solenoid for internal short by measuring resistance to case ground
4
Step 4: Inspect wiring harness routing for pinch points, abrasion, or contact with hot engine components
5
Step 5: Monitor circuit voltage with scan tool during valve activation to identify intermittent shorts
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
The PCM has detected voltage on the Fuel Shutoff Valve B control circuit that is lower than expected specifications. This indicates a short to ground or excessive resistance in the circuit preventing proper valve operation.
The most common cause of P2666 (Fuel Shutoff Valve "B" Control Circuit Low) is: Short to ground in fuel shutoff valve control circuit wiring
Typical repair costs for P2666 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may experience reduced power or rough running. Safe to drive cautiously to repair facility, but address promptly to prevent potential stalling.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2666 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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