P2751

Code

Generic P — Powertrain

Intermediate Shaft Speed Sensor C Circuit No Signal

Brand: Generic

Type: P — Powertrain

Views: UK: 23 EN: 43 RU: 27

AI status

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Page language: EN

Causes

Open or short in sensor C wiring harness
Failed intermediate shaft speed sensor (Sensor C)
Corroded, loose or damaged connector(s)
Missing/damaged reluctor tone wheel or sensor air gap excessive
Failed or intermittent reference power or ground from PCM
PCM or transmission control module fault (rare)

Symptoms

Check engine / transmission warning light illuminated
Transmission may go into limp / failsafe mode
Harsh, delayed, or erratic shifting
Incorrect shift points or inability to shift
Transmission may not lock torque converter correctly

What to check

Read freeze frame and freeze data with a scan tool; note related transmission codes
Visually inspect sensor, wiring, and connector for damage, corrosion, or contamination
Back-probe sensor connector for reference voltage, ground and signal with key on/cranking
Check continuity from sensor connector to PCM for opens/shorts
Measure sensor resistance (if specified) and compare to service spec
Use oscilloscope to verify sensor waveform while cranking or driving

Signal parameters

Hall-effect (three-wire) sensors: reference typically 5 V, ground, signal ~0–5 V square wave at speed
Variable reluctance (two-wire) sensors: AC voltage that increases with shaft speed (may be 0.1–12 VAC)
Typical DC resistance for VR sensors often in hundreds to low thousands of ohms (vehicle-specific)
Signal frequency/pulse rate increases proportionally with intermediate shaft speed
Expected: regular pulse pattern when shaft turns; no pulses = no signal

Diagnostic algorithm

Verify code and check for additional transmission or speed sensor codes; record freeze frame data.
Visually inspect the intermediate shaft speed sensor C connector and wiring for damage, corrosion, pin push-out or contamination.
With ignition ON (engine off) back-probe the sensor connector and confirm reference voltage (if three-wire) and good ground. If reference or ground missing, trace to PCM.
Crank engine or rotate transmission input while monitoring signal line with a multimeter (AC for VR) or oscilloscope. Look for pulses or AC voltage. No pulses indicates sensor/circuit problem.
Check sensor resistance per service specifications; compare to known good sensor if spec unavailable. Open or out-of-range reading → replace sensor.
Perform continuity and short tests between sensor signal and PCM terminal. Repair any open or short-to-ground/power found.
Inspect tone wheel/reluctor and sensor air gap; repair or replace damaged reluctor or adjust gap to spec.
Repair wiring/connector faults or replace sensor as indicated. Clear codes and road test to confirm proper operation.
If fault returns after sensor and wiring verified, consider PCM/transmission control module diagnosis or replacement as a last resort.

Likely causes

Damaged wiring or connector to the intermediate shaft speed sensor (most common)
Failed speed sensor (wear, water intrusion)
Corroded connector or poor ground

Fault status

⚠️ Status

P2751 - Intermediate Shaft Speed Sensor C Circuit: No Signal detected from intermediate shaft speed sensor C. The PCM expected pulses from this sensor and found none, indicating a sensor or wiring fault.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 3.0 hours