Powertrain, generic · Fuel and air metering (injector circuit)

P0291 Cylinder 11 Injector A Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0291 means the control wire of the cylinder 11 injector – the side the engine module switches to ground – is shorted to ground. GM detects this with the driver off: on direct injection at 1 V or less, on port injection and Duramax diesels at 0.5 Ω or less to ground. Ford's 6.7 diesel has its driver chip report the short within 0.3 s. Most systems switch the warning light on in the first trip (some GM port-injection engines and Saab's 2.0 turbo after two) and shut the affected injector off, so the cylinder misfires. Ford petrol engines report all injector circuit faults as P0201 ff instead. Cylinder 11 exists only on twelve-cylinder engines; no manufacturer document using this code was found – GM and Ford documents stop at cylinder 8 – so the description follows CARB and the codes for cylinders 1–8.

Likely causes

Control wire of the cylinder 11 injector chafed to ground in the harness
Injector connector damp or corroded, leakage to ground
Injector shorted to its housing internally
Open control wire (on some GM port-injection drivers this also reads low; P020x sets too)
Driver stage in the engine module faulty

Symptoms

  • Check engine light on
  • Misfire and rough running, misfire code P0311
  • Loss of power, rough idle
  • Injector shut off, limp mode possible on diesels

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–800
Time0.5–4 h

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

Parts involved

fuel injector cylinder 11injector wiringengine control module

Related codes

P0292P0211P02F8P0293P0311P0300

References: law.cornell.edu, gsi.ext.gm.com.