Question 1

What does GM fault code B0081 mean?

Accepted Answer

B0081 (Safety Restraints (SRS)): Service Airbag Array Note On Dash Fix: LOGIC: Passenger Presence System (PPS) Module Serial Data Link Missing.

ACTION: Inspect the tiny auxiliary module sub-harness tracking lines hidden beneath the passenger seat lower frame cushion assembly layout tracks.

Question 2

What does GM fault code B1000 mean?

Accepted Answer

B1000 (Cabin Electronics): Dead Dash / Power Windows Inop Fix: LOGIC: Body Control Module (BCM) Internal Electronic Hardware Error.

ACTION: Perform a hard battery reset (disconnect negative terminal for 10 mins). Check BCM power feeds under load. If reference drops pass, replace and program the BCM.

Question 3

What does GM fault code B1000 mean?

Accepted Answer

B1000 (BCM / Hardware): No Cranking / Dash Warning Frenzy Fix: LOGIC: Electronic Control Unit (BCM / SDM) Internal Performance Malfunction.

ACTION: Inspect main BCM ground lugs on the A-pillar and kick panels. Check clean 12V constant battery power feeds under load; if power and grounds are pristine, replace and reprogram BCM/SDM module.

Question 4

What does GM fault code P0191 mean?

Accepted Answer

P0191 (Fuel System): Limp Mode / Long Extended Crank Fix: LOGIC: Fuel Rail Pressure Sensor Circuit Range/Performance.

ACTION: Match active rail pressure transducer telemetry readings against a manual fuel gallery shop gauge. Check for an unsealed pressure relief valve.

Question 5

What does GM fault code P025A mean?

Accepted Answer

P025A (Fuel System): Extended Crank / Hard Start Fix: LOGIC: Fuel Pump Module Control Circuit Open.

ACTION: Locate the fuel pump driver module (FPDM). Perform a voltage drop test on the module's main power feed and ground circuit under load.

Question 6

What does GM fault code P050B mean?

Accepted Answer

P050B (Ignition): Rough Cold Start Idle / Rattle Fix: LOGIC: Cold Start Ignition Timing Performance.

ACTION: Check for localized carbon crust layer loading on the intake valve stems. Verify Engine Coolant Temp (ECT) sensor accuracy scaling parameters.

Question 7

What does GM fault code P068A mean?

Accepted Answer

P068A (Electrical / Engine): Random ECM Reset / Delayed Sleep Fix: LOGIC: ECM / PCM Power Relay De-Energized Performance - Too Early.

ACTION: Test main ECM power relay socket terminals for corrosion. Measure voltage drop across relay contacts under load, and verify battery permanent unswitched 12V supply line integrity.

Question 8

What does GM fault code P0708 mean?

Accepted Answer

P0708 (Transmission Range): No-Crank / Range Shift Inhibited Fix: LOGIC: Transmission Range Sensor (Neutral Safety / PRNDL) High Input.

ACTION: Inspect the dual-connector Neutral Safety Switch (NSBU switch) mounted externally on the driver's side of the transmission case. Check for backed-out terminal pins, water intrusion, or internal corrosion. Realign the switch using the neutral alignment line or replace.

Question 9

What does GM fault code P0717 mean?

Accepted Answer

P0717 (Speed Sensing): Harsh Shifts / Range Inhibit / No Lockup Fix: LOGIC: Turbine / Input Shaft Speed (ISS) Sensor No Signal.

ACTION: Remove the ISS sensor from the front driver-side area of the transmission case. Clean metal shavings off the magnetic tip. Measure coil resistance (spec: ~200–400Ω); trace wiring back to the TCM for broken twisted pairs.

Question 10

What does GM fault code P0729 mean?

Accepted Answer

P0729 (Gear Ratio): Slipped 6th Gear / Harsh Downshift to 4th Fix: LOGIC: Incorrect 6th Gear Ratio (C1/C4 Clutch Pack Slip).

ACTION: Check ATF fluid level and clarity. Connect a scan tool to monitor turbine speed vs. output shaft speed when shifting into 6th gear. If slip exceeds 150 RPM, perform a hydraulic air pressure check on the C1 and C4 clutch apply circuits on the bench.

Code	System	Symptom	Full fix
B0081	Safety Restraints (SRS)	Service Airbag Array Note On Dash	View fix
B1000	Cabin Electronics	Dead Dash / Power Windows Inop	View fix
B1000	BCM / Hardware	No Cranking / Dash Warning Frenzy	View fix
P0191	Fuel System	Limp Mode / Long Extended Crank	View fix
P025A	Fuel System	Extended Crank / Hard Start	View fix
P050B	Ignition	Rough Cold Start Idle / Rattle	View fix
P068A	Electrical / Engine	Random ECM Reset / Delayed Sleep	View fix
P0708	Transmission Range	No-Crank / Range Shift Inhibited	View fix
P0717	Speed Sensing	Harsh Shifts / Range Inhibit / No Lockup	View fix
P0729	Gear Ratio	Slipped 6th Gear / Harsh Downshift to 4th	View fix
P0746	Pressure Control	Harsh Clunk on Shift / Stuck in 3rd Limp	View fix
P1101	Air Intake	Stalling / Service StabiliTrak Message	View fix
P1101	Air Intake	Stalling / Service Stability Message	View fix
P2101	Air Intake	Reduced Engine Power / Forced Idle	View fix
Service Light Indicator	—	—	View fix

GM Fault Codes

Ready to take control of your fleet maintenance?

Other manufacturers