Ignition Switch Run Position Circuit Low
The ignition switch Run-position input reads stuck low — short to ground or a permanently closed contact. The ECM cannot tell when the operator releases the switch from Run, so accessory and crank logic gets confused.
Affected components
- Ignition switch
- Wiring harness
Common causes
- High likelihood: Run input wire shorted to ground
- Medium likelihood: Switch contact stuck closed
- Low likelihood: Connector pins corroded - high contact resistance
Diagnostic notes
- The malfunction indicator lamp may illuminate
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.