C0235 – Rear Wheel Speed Signal Circuit Open

System: Chassis | Standard: ISO/SAE Controlled | Fault type: Circuit/Open

Official meaning: Rear Wheel Speed Signal Circuit Open

Definition source: SAE J2012 naming/structure guidance

What Does C0235 Mean?

C0235 – Rear Wheel Speed Signal Circuit Open is an ISO/SAE controlled chassis DTC that sets when the vehicle’s chassis control system detects an open circuit in the rear wheel speed signal circuit. The authoritative meaning is: Rear Wheel Speed Signal Circuit Open.

An “open” circuit means the control module cannot see a complete electrical path for the rear wheel speed signal. This can occur from a disconnected connector, a broken wire, a terminal that has backed out, severe corrosion, or another loss of continuity in the circuit. When the module cannot receive a valid rear wheel speed signal, it may disable or limit functions that rely on wheel speed inputs (such as ABS, traction control, and stability control), because it cannot reliably calculate rear wheel speed.

Quick Reference

• Code: C0235
• Official Title: C0235 – Rear Wheel Speed Signal Circuit Open
• Official Meaning: Rear Wheel Speed Signal Circuit Open
• System: Chassis
• Standard classification: ISO/SAE Controlled
• Fault type to enforce: Circuit/Open
• What it indicates: Loss of continuity/open in the rear wheel speed signal circuit resulting in an unavailable or invalid rear wheel speed input
• Likely effects: ABS/traction/stability control may be limited or disabled; warning indicators may illuminate

Symptoms

C0235 can be accompanied by one or more of the following symptoms, depending on vehicle configuration and when the open circuit occurs:

• ABS warning light illuminated and ABS operation may be disabled or reduced
• Traction control indicator illuminated and traction control may be disabled or reduced
• Stability control indicator/message and stability control may be disabled or reduced
• Stored chassis DTC C0235 in the ABS/chassis module
• Intermittent warning lights if the circuit opens and reconnects due to movement or vibration
• Live data anomaly where rear wheel speed information is missing, stuck at a value, or drops out compared to other wheels (as shown by a scan tool capable of chassis data)
• Change in brake feel during hard braking if ABS is unavailable (pedal behavior depends on system design)

Common Causes

C0235 is a circuit/open fault, so causes should be evaluated with continuity, terminal fit, and wiring integrity in mind:

• Open in the rear wheel speed sensor signal circuit wiring (broken conductor, cut harness, damage at a flex point)
• Rear wheel speed sensor connector issue (disconnected connector, corrosion, moisture intrusion, damaged seal)
• Terminal fit problem (backed-out terminal, spread terminal, bent pin, poor pin retention)
• Open inside the rear wheel speed sensor (internal failure resulting in no signal output)
• Power supply/ground issue affecting the circuit (where applicable to the sensor type and vehicle design)
• Harness routing/retention problem causing the wiring to be pulled, pinched, or damaged by suspension travel
• Control module connector/pin issue at the chassis/ABS module side (poor connection or pin damage). Module faults should only be considered after circuit checks.

Diagnosis Steps

Use a scan tool that can access chassis/ABS data, a digital multimeter (DMM), and the correct wiring diagram for the specific vehicle. The goal is to confirm the fault is truly an open circuit and locate where continuity is lost.

1. Confirm C0235 is present in the chassis/ABS module. Record stored status (current/pending/history) and any available event data to understand when the fault was detected.
2. Check for additional chassis DTCs. Related wheel speed or power/ground codes can change the diagnostic direction. Address foundational power/ground or communication faults first if present.
3. Review live wheel speed data (if available). Compare wheel speed readings while performing a safe test (road test or approved lift procedure). A missing or non-responsive rear wheel speed input supports a circuit/open direction.
4. Perform a visual inspection at the rear wheel area. Inspect the sensor pigtail, harness routing, clips, and protective sheathing. Look for abrasion, pinching, pulled wiring, or contact points that could cause an open.
5. Inspect the rear wheel speed sensor connector. Verify it is fully seated and locked. Check for corrosion, moisture, damaged seals, bent pins, or terminals that appear pushed back.
6. Inspect intermediate connectors (if equipped) and the module-side connector. Many vehicles use body connectors between the wheel and the module. Ensure each connection is secure and free of terminal damage.
7. Check power and ground at the sensor (where applicable). Some sensor designs require a power feed and ground. Using the wiring diagram, verify correct supply voltage and ground integrity at the sensor connector.
8. Test continuity of the rear wheel speed signal circuit. With the circuit safely isolated (as appropriate), measure end-to-end continuity between the sensor connector and the chassis/ABS module connector. An open will show no continuity (or unstable readings).
9. Check for high resistance and intermittent opens. Do not rely only on a continuity beep. Measure resistance and perform a controlled wiggle test along the harness and at connectors to reveal intermittent opens.
10. Verify terminal tension/pin fit. If continuity is inconsistent, use proper terminal test tools to check whether terminals grip correctly and are not spread, loose, or partially backed out.
11. Validate the repair. After correcting the fault, clear DTCs and perform a verification test under conditions that allow the system to monitor wheel speed inputs. Recheck for codes and confirm wheel speed data remains stable.

Possible Fixes

Repairs for C0235 should directly address the open circuit identified during testing:

• Repair or replace damaged wiring in the rear wheel speed signal circuit (proper splicing/repair methods, correct wire gauge, sealed repairs, and restored harness protection)
• Restore connector integrity by cleaning/drying, reseating, and correcting lock engagement; replace damaged connector housings or seals when required
• Repair/replace terminals that are corroded, bent, spread, or backed out to restore reliable contact and retention
• Restore sensor power/ground (where applicable) by repairing opens in feeds/grounds, addressing damaged splices, or correcting poor ground connections identified in testing
• Replace the rear wheel speed sensor only if testing confirms the sensor itself is open/not producing a valid output and the circuit wiring/connectors are verified intact
• Address module-side connector issues if pin fit, corrosion, or damage is found at the chassis/ABS module connector

Can I Still Drive With C0235?

In many cases the vehicle will still move and steer normally with C0235 present, but driving should be treated with increased caution. Because C0235 indicates an open circuit in the rear wheel speed signal circuit, the chassis system may disable or limit ABS, traction control, and stability control functions that depend on accurate wheel speed inputs.

If warning lights are on, assume those features may not operate as intended. Use conservative driving habits: increase following distance, avoid aggressive acceleration and abrupt braking, and be especially cautious in low-traction conditions. Diagnose and repair the open circuit promptly due to the safety implications of reduced chassis control functionality.

Repair Costs

Repair cost depends on whether the confirmed root cause is wiring, connector condition, a switch or module issue, or the labor needed to diagnose the fault correctly.

Last updated: March 24, 2026