Code
C1246
HUMMER
C — Chassis
Brake Lining Wear Circuit Open
AI status
Completed
Completed
100%
Causes
- Broken or chafed sensor wire at the caliper or suspension movement point
- Corroded, loose or disconnected connector at the wear sensor or control module
- Failed or damaged pad wear sensor (broken element)
- Aftermarket or replacement pads without a wear sensor installed
- Faulty ABS/Brake control module or internal driver fault (less common)
- Water intrusion or corrosion in harness or connector
Symptoms
- Brake pad wear warning light or BRAKE message on dash
- Illumination of ABS or traction control warning lamps in some systems
- One wheel brake pad not reporting wear (uneven wear may go unnoticed)
- Stored DTC C1246 in chassis control/ABS module
What to check
- Read and record freeze-frame and related ABS/chassis codes with a scan tool
- Visually inspect all four pad wear sensors, connector plugs and harness routing at each wheel/caliper for damage, corrosion, or separation
- Separate connector and inspect terminals for corrosion, bent pins, or water intrusion
- Check for aftermarket pads or missing sensor clips on replaced pads
- Perform a wiggle test on the harness while monitoring for change in status with a scan tool
Signal parameters
- Intact pad-wear sensor: circuit shows continuity (low resistance). Exact resistance varies by design; consult service manual. Open circuit: infinite/OL resistance.
- Some systems provide a switched voltage from module — expect ~0–12 V depending on design. With sensor connected and intact voltage may be pulled to ground or to reference; consult vehicle wiring diagram.
- Compare readings to service manual values for the specific wheel/sensor.
Diagnostic algorithm
- Use a scan tool to confirm C1246 and check for any related codes (ABS, wheel speed, other C12xx codes). Record which wheel is indicated if available.
- Visually inspect the pad wear sensor and harness at the wheel specified. Look for chaffing where the lead passes through brackets or rubber boots.
- Disconnect the suspect sensor connector and measure resistance across the sensor. If resistance is infinite/OL, the sensor is open and should be replaced.
- If the sensor shows continuity, check continuity between the sensor connector pin and the ABS/control module connector pin. Repair any open circuit in the harness (splice, replace harness section, repair terminal).
- If wiring and sensor check good, inspect module connector for corrosion and check for proper reference voltage/ground at the module pin with a wiring diagram. Replace or repair terminals as needed.
- If wiring and sensor are good and module outputs are correct, suspect internal module fault and follow factory procedures to verify/replace the ABS/chassis control module.
- After repair or replacement, clear codes, perform relearn procedures if required, and test drive to confirm code does not return.
Likely causes
- Broken/frayed sensor lead at caliper (most common)
- Disconnected or corroded connector at wheel or module
- Damaged pad wear sensor element
Fault status
Status
Brake Lining Wear Circuit Open — the brake pad wear sensor circuit is reporting an open (no continuity). This will trigger a brake pad wear/maintenance warning and should be inspected and repaired.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Repair manuals
Manual library for HUMMER
138
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