Network, generic (extended)

U3008 Control Module Ground A

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

Modules that switch large currents are often grounded through two separate wires, and U3008 marks the loss of ground A. GM's 19OBDG03B brake module measures the voltage on both grounds and forms (G1 − G2)/(G1 + G2); each wire should carry half the current, so a result above 0.9 for 200 ms means ground 1 is gone, Type A with MIL. Ford's TSB 26-2150 for 2025–2026 Explorer, Police Interceptor and Aviator ties U3008:1B in the steering module, the byte meaning resistance too high, to ground G104 or G116 on the passenger frame rail; the repair enlarges the hole and fits a self-tapping M8 bolt. On the road this shows as a steering assist warning and heavier steering. Mazda uses U3008:01 on CX-90 and CX-70 plug-in hybrids for an over-current or voltage fault in the backup power unit instead.

Likely causes

Loose or poorly clamped ground eyelet at the body or frame
Corrosion or paint under the ground connection raising resistance
Broken or chafed ground wire A in the harness

Symptoms

  • Steering assist or brake system warning in the cluster
  • Reduced power steering assist or limited ABS function
  • Check engine light where the maker classes it as MIL-relevant

Repair estimate

DifficultyMediumDIY possible
Parts and labour€10–250
Time0.5–2 h

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

Parts involved

module ground aground strap

Related codes

U3009U3015U3016U3006

References: gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.