Ford C1165 Code: RR Wheel Speed Sensor Input Circuit Failure
Ford's ABS module detected an open or short in the right rear wheel speed sensor wiring or sensor.
Safety first · Consult a professional
- Braking system affected: ABS may be disabled. Drive carefully and have it checked promptly.
At a glance
Severity: Moderate
- Meaning
- RR Wheel Speed Sensor Input Circuit Failure
- System
- Brakes, ABS & Chassis · Chassis
- Safe to drive?
- With caution
- Typical repair cost
- $0–$600
- DIY difficulty
- Moderate
C1165 is set by the ABS module of four-sensor Ford vehicles when the right rear (passenger-side rear) sensor circuit fails its electrical check: the loop is open, shorted to ground or shorted to power. It is Ford's counterpart to generic C0050 and shows up on vehicles such as the Escape, Focus, Fusion, Edge, Explorer and newer F-150 generations that have a sensor at each rear wheel. The rear sensor lead has a long, exposed route along the trailing arm or axle to a connector under the body, and on many crossovers and cars the sensor sits in a rear knuckle bore that rusts badly. Rust swelling in that bore can crack the sensor's plastic housing and let water in, which is why a rear sensor on an older Ford often fails electrically rather than just losing its signal.
Can I keep driving? You still have full normal braking, but ABS, traction and stability control are off, and the rear wheels can lock and let the car step out under hard braking. Drive smoothly, especially on slippery roads, and repair it soon.
How to read C1165
- C Chassis
- 1 Manufacturer-specific
- 1 Brakes, ABS & Chassis
- 65 Specific fault
Symptoms
- ABS and traction control lights on, often right at start-up
- Stability control or AdvanceTrac disabled message
- Right rear sensor lead visibly hanging loose or rubbing under the car
- Code appeared after rear brake, bearing, suspension bushing or exhaust work
- Rear wheel bearing growl on the right side on some vehicles
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Right rear sensor housing cracked by rust in the knuckle bore, letting water short the sensor
- Lead damaged along the trailing arm, lower control arm or axle (broken clips, chafe, road debris)
- Corroded underbody connector near the rear subframe or fuel tank
- Lead stretched or pinched during rear brake, hub or suspension work
- Rear hub bearing assembly with integrated sensor failed (on models where the sensor is part of the hub)
- ABS module input fault
Diagnosis step by step
Confirm it's a circuit fault
Clear the ABS codes and cycle the key without driving. If C1165 returns immediately, test the wiring and sensor; if it only returns after driving, look for a signal problem instead.
Tools: OBD-II scanner
Split the circuit at the underbody connector
Find the right rear sensor connector under the car and unplug it. Measure toward the sensor and toward the ABS module separately; this tells you in one step which half of the circuit holds the fault.
Tools: Multimeter, Flashlight
Compare with the left rear
Key on, measure the supply the ABS module delivers at the right rear connector and compare it with the left rear connector. The two sides should match; a missing or low supply on the right points to the harness or module.
Tools: Multimeter
Remove and inspect the sensor
Soak the sensor bolt and bore with penetrating oil, then twist the sensor out gently. Look for cracks in the housing, green corrosion at the tip and rust scale packed in the bore.
Tools: Screwdriver, Pliers, Flashlight
Clean the bore before fitting a new sensor
Remove rust from the bore with a small wire brush or a suitable reamer until the new sensor slides in by hand and sits flat. Forcing a sensor into a rusty bore cracks it and sets the same code again.
Tools: Flashlight, Gloves
Route, clip and verify
Clip the lead along its original route with enough slack for full suspension travel. Clear the codes, cycle the key and drive over some bumps to confirm the circuit stays good.
Tools: OBD-II scanner, Torque wrench
Where the parts are
- 1Battery
- 2Alternator
- 3Engine computer (ECM)
- 4CAN bus
- 5Transmission
- 6Wheel speed sensor
- 7High-voltage battery
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Clean and reseal the underbody connector | Yes | $0–$90 |
| Replace right rear wheel speed sensor and clean bore | Yes | $90–$320 |
| Repair rear sensor harness section | No | $100–$300 |
| Replace rear hub bearing assembly (integrated sensor or damaged mount) | No | $250–$600 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Emissions / smog test impact
Depends
C1165 doesn't affect a US emissions test. In states with a safety inspection, the ABS warning light it turns on can cause a failure.
Frequently asked questions
Why does the rear sensor break when I try to remove it?
Rust grows around the sensor body in the knuckle and locks it in place. Soak it with penetrating oil, twist rather than pry, and expect to clean the bore if the old one breaks.
Could C1165 be caused by the left rear?
Not normally; C1165 names the right rear circuit. If C1165 and C1175 appear together, look for something shared, such as a damaged harness section across the rear subframe or the ABS module.
Does my F-150 have separate rear sensors?
Newer F-150 generations have one sensor at each rear wheel, so C1165 applies. Trucks and vans with a single rear sensor in the differential housing, such as many Super Duty and E-Series models, typically log rear sensor faults as C1175 instead.
Do I have to replace the whole rear hub?
Only if the sensor is built into the hub assembly on your model or the hub's sensor mount is damaged. Otherwise the sensor is a separate bolt-in part.
Sources
- Manufacturer public service information (cross-checked)
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