Diagnostic Trouble Code (DTC) List

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Diagnostic Trouble Code (DTC) List
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Diagnostic Trouble Code (DTC) List
G01706123Courtesy of GENERAL MOTORS CORP.
DIAGNOSTIC TROUBLE CODE (DTC) DEFINITION

DTC Description
C0221  RF Wheel Speed Sensor Circuit Open
C0222  RF Wheel Speed Signal Missing
C0223  RF Wheel Speed Signal Erratic
C0225  LF Wheel Speed Sensor Circuit Open
C0226  LF Wheel Speed Signal Missing
C0227  LF Wheel Speed Signal Erratic
C0229  Drop Out Of Front Wheel Speed Signals
C0235  Rear Wheel Speed Signal Circuit Open
C0236  Rear Wheel Speed Signal Circuit Missing
C0237  Rear Wheel Speed Signal Erratic
C0238  Wheel Speed Mismatch
C0241  EBCM Control Valve Circuit
C0245  Wheel Speed Sensor Frequency Error
C0254  EBCM Control Valve Circuit
C0265  EBCM Relay
C0266  EBCM Relay Circuit
C0267  Pump Motor Circuit Open/Shorted
C0268  Pump Motor Circuit Open/Shorted
C0269  Excessive Dump/Isolation Time
C0271  EBCM Malfunction
C0272  EBCM Malfunction
C0273  EBCM Malfunction
C0274  Excessive Dump/Isolation Time
C0279  Powertrain Configuration Not Valid
C0281  Brake Switch Circuit
C0283  Traction Switch Shorted To Ground (W/NW7)
C0284  EBCM Malfunction
C0287  Delivered Torque Circuit
C0290  Lost Communications With PCM
C0292  Lost Communications With PCM
C0297  Powertrain Configuration Data Not Received
C0298  Powertrain Indicated Traction Control Malfunction
P1504  Vehicle Speed Output Circuit
P1571  TCS PWM Circuit No Frequency
P1644  P1644: Delivered Torque Output Circuit
P1689  Traction Control Delivered Torque Circuit
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.