C0045 Left rear wheel speed sensor circuit fault (GM)

C0045 left rear wheel speed sensor circuit

Severity not verified — if the car runs badly, have it inspected

The sources describe the fault and lamps but not drivability; ABS and stability systems are safety-critical, so have it checked.

It gets more serious if:

  • Stop: The red brake warning lamp comes on, the pedal feels soft or low, or steering assist is lost along with the ABS lamp.

Safety-critical system: explanation only, no DIY steps. Source: how we rate severity

C0045 in short

On GM vehicles C0045 is a left rear wheel speed sensor circuit fault set by the brake control module. GM bulletins trace it to rear sensor harness or connector problems, and owners report bad sensors or hub rings. ABS, traction and Stabilitrak may switch off; ordinary braking usually continues.

The brake control module watches a speed signal at each wheel. C0045 means the left rear signal is missing or implausible, so anti-lock, traction and stability control cannot trust that wheel and the module turns them off.

GM bulletins usually list C0045 with C0050 (the other rear wheel). Documented causes include a wire pulled out of a crimp at a rear connector (Express, Savana), a wire break inside the harness at X411 (Equinox, Terrain), and oil at the sensor (2004 Malibu). One Cadillac SRX owner had a broken sensor encoder ring on the left rear hub, and an Equinox owner was told to replace the hub bearing assembly.

This page speaks only for GM; other makers use C0045 differently. Brakes are safety-critical, so there are no do-it-yourself steps.

Pick your make

C0045 is a manufacturer-specific code: its meaning depends on who built the car.

Other makes: meaning not verified. Check with a scan tool that reads manufacturer definitions.

Most likely causes

  1. Rear wheel speed sensor harness or connector fault

    Supported by vehicle data
    Why it ranks here
    Several GM bulletins (08-05-25-002, PIT-4648-B, PIT5171B) name harness breaks or terminal crimps at rear connectors for C0045 and C0050.
    What would change this
    Rises if the signal flickers when the harness or connector is moved. Falls if harness and terminals test normal.
    How to test the brake system control module (abs module)

  2. Left rear sensor, hub or encoder ring

    Supported by vehicle data
    Why it ranks here
    A Cadillac SRX complaint traced C0045 to a broken encoder ring and an Equinox service center advised a hub bearing assembly; GM 01885 names oil at the rear sensor.
    What would change this
    Rises if the ring is cracked or oily or the sensor signal is erratic. Falls if ring and signal look normal.
    How to test the brake system control module (abs module)

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Ask a shop to read the ABS codes, check the left rear wheel speed sensor signal, its harness and connector, and search GM bulletins for your VIN.

    Best left to a shop

    Warning:Brake faults are safety-critical; leave diagnosis and repair to a qualified shop.

Symptoms

  • ABS lamp on
  • Traction off or Service Stabilitrak message
  • Red brake lamp on or pedal feels wrong Gets more serious: stop and have it checked.

How to fix

This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.

Parts and cost context

  • Brake system control module (ABS module):Rear sensors, hub assemblies and harness repairs are the parts named by bulletins and owners; labor varies, get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Saturn

  • 2008 · Vue

    Supported by vehicle data

    GM PIT4586 and 08-05-25-002 cover C0045 and C0050 on the 2008 Vue and point to the rear sensor harness. Bulletin currency not verified.

  • PIT4586Status unverified

    ABS codes C0045 and/or C0050 set in the EBCM

    2008vue · NHTSA 10024709

    Wheel speed sensor codes C0045 and C0050 set in the EBCM.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 08-05-25-002Status unverified

    ABS lamp, C0045 and/or C0050

    2008vue · NHTSA 10025128

    Inspect connector X408 or the left/right rear wheel speed sensor harness.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Chevrolet

  • 2008–2010 · Express

    Supported by vehicle data

    GM PIT-4648-B names a wire pulling out of a terminal crimp. Bulletin currency not verified.

  • 2010–2012 · Equinox

    Supported by vehicle data

    GM PIT5171B names a wire break inside the harness at X411; an owner of a 2012 Equinox was told to replace a hub bearing assembly. Bulletin currency not verified.

  • 2004 · Malibu

    Supported by vehicle data

    GM 01885 names oil at the rear wheel speed sensor. Bulletin currency not verified.

  • PIT-4648-B (chevrolet)Status unverified

    ABS light or Service Stability message with C0045 and/or C0050

    2008–2010express · NHTSA 10036515

    Wire pulling out of a crimp at connector X413 or X414 can cause the code.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • PIT5171B (chevrolet)Status unverified

    Intermittent Service Traction/Stability or ABS message with C0045 and C0050

    2010–2012equinox · NHTSA 10112913

    Inspect connector X411 and the harness for a wire break.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 01885Status unverified

    ABS DTC C0045 or C0050, oil at rear wheel speed sensor

    2004malibu · NHTSA 10006487

    Oil contamination at the rear wheel speed sensor.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

GMC

  • PIT-4648-B (gmc)Status unverified

    ABS light or Service Stability message with C0045 and/or C0050

    2008–2010savana · NHTSA 10036515

    Wire pulling out of a crimp at connector X413 or X414 can cause the code.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • PIT5171B (gmc)Status unverified

    Intermittent Service Traction/Stability or ABS message with C0045 and C0050

    2010–2012terrain · NHTSA 10112913

    Inspect connector X411 and the harness for a wire break.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Cadillac

  • 2011 · SRX

    Supported by vehicle data

    A 2011 SRX complaint reports C0045 from a broken left rear sensor encoder ring at about 96,000 miles.

  • C0050Right rear wheel speed sensor circuit fault (GM)

    Same system Supported by vehicle data

    GM bulletins list C0045 with C0050 for the rear wheel speed sensor circuits.

  • C0035Left front wheel speed sensor circuit fault (GM)

    Same system Supported by vehicle data

    GM bulletin PIC5837 lists C0035, C0040, C0045 and C0050 together as wheel speed sensor codes.

All ABS, traction and stability control codes

C0045 questions

What does C0045 mean on a GM vehicle?

A left rear wheel speed sensor circuit fault in the brake control module. C0050 is the matching rear-wheel code.

Is it safe to drive with C0045?

Normal braking usually still works, but anti-lock and stability control may be off. Stop if the red brake lamp comes on or the pedal feels wrong.

Sources and review

  1. GM 08-05-25-002: ABS code C0045 and/or C0050 (inspect connector X408 or left/right rear wheel speed sensor harness) — General Motors via NHTSA
  2. NHTSA complaints ODI 11219167 (Cadillac SRX) and 11165895 (Chevrolet Equinox) — NHTSA ODI
  3. GM PIT-4648-B: ABS light and/or Service Stability message with C0045 and/or C0050 — General Motors via NHTSA
  4. GM PIT5171B: intermittent Service Traction/Stability, ABS or AWD message with C0045 and C0050 symptom 06 — General Motors via NHTSA
  5. GM 01885: ABS DTC C0045 or C0050, oil at rear wheel speed sensor — General Motors via NHTSA
  6. GM PIT4586: ABS codes C0045 and/or C0050 wheel speed sensor codes set in the EBCM — General Motors via NHTSA
Last reviewed
Written by
Saurabh K.
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