Powertrain, generic (extended)

P2A33 AFCM Power Relay Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2A33 concerns the control line that grounds the coil of the relay supplying the gas control module. Low means this line already sits near zero volts while the driver is switched off. A chafed wire touching the body is the classic finding; a coil with shorted windings can give the same picture. Since the coil is then permanently grounded, the relay may stay energised after the key is off, keeping the gas module awake and draining the battery overnight. Nobody publishes this code for a production gas system. Saab's GM Europe V6 manual, written for the engine relay twin P0686, lets the test run only between 10 and 18 V supply with the engine turning above 80 rpm and classes it as a Type C code, meaning no warning lamp there. CARB expects actuator outputs to be checked for such shorts.

Likely causes

Control wire chafed through and touching ground
Shorted turns in the relay coil
Moisture in the relay socket bridging to ground

Symptoms

  • Check engine light, depending on calibration
  • Battery flat after the vehicle has been parked
  • Gas module stays active after ignition off

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–350
Time0.5–2.5 h

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

Parts involved

afcm power relayafcmwiring harness

Related codes

P2A32P2A34P2A36P0686U0108

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