P26B4 code meaning
Fuel Shutoff Valve A Control Circuit Stuck On
Powertrain system Generic code P26xx codes Check engine light
What P26B4 means
P26B4 is the opposite failure to P26B3: shut-off valve A stays open or energised when the module wants it closed. No manufacturer documents P26B4 in public sources. On the Roush propane system for Ford trucks, valve A is the tank solenoid (its open-circuit code is P0005), and GM's 2015 Impala Bi-Fuel uses two normally closed CNG cut-off valves that the ECM opens only in gas mode while the engine cranks or runs. A valve that cannot close defeats that safety function, so fuel may keep flowing into the lines after shut-off. Typical causes are a short to voltage on the control wire, a stuck driver or relay, or a mechanically jammed valve. CARB requires output monitoring. Have it fixed promptly; close the manual tank valve if fuel can be smelled.
P26B4 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 3.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P26B4
- Check engine light
- Fuel odour after shut-off
- Fuel pressure remains in the lines with the engine off
Common causes of P26B4
- Most likelyControl wire shorted to battery voltage
- PossibleSupply relay or driver stuck on
- PossibleValve A mechanically jammed open
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel shutoff valve aSolenoid
What each part of P26B4 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 6 | Area: computer (engine control module) and output circuits. |
| B4 | The exact fault in that area. |
What to do next
- Note P26B4 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P26B4
What does P26B4 mean?
P26B4 means "Fuel Shutoff Valve A Control Circuit Stuck On". P26B4 is the opposite failure to P26B3: shut-off valve A stays open or energised when the module wants it closed. It is a generic code, so it means the same on every make.
Is it safe to drive with P26B4?
Drive gently and only to a workshop. With P26B4 the car can go into limp mode (reduced power) to protect itself.
Will P26B4 fail an emissions test?
Yes, it can. P26B4 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P26B4 to fix?
Difficulty: hard. A typical repair takes 1 to 3.5 hours of work. This is a job for a workshop.
Will P26B4 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.