P26B6 Fuel Shutoff Valve B Control Circuit Stuck On

P26B6 reports that shut-off valve B cannot be switched off: the control circuit or the valve remains in the on state after the module removes the command. No manufacturer documents P26B6 publicly. Where valve B is defined, it is a solenoid on the low-pressure side, for example the supply solenoid of the Roush propane rail pressure module (circuit code P2665) or, on GM's CNG Impala, one of two normally closed cut-off valves, the other sitting at the tank. Possible reasons are a control line shorted to power, a welded relay contact or a valve stuck open. Unlike P26B5, the engine usually still starts; the concern is that fuel is no longer sealed off when parked. CARB requires output components to be monitored. Repair soon and use the manual valve if gas is smelled.

Likely causes

Symptoms

• Check engine light
• Fuel odour near the engine or regulator after shut-off

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, roushcleantech.com, static.nhtsa.gov.