P0937

Code

Generic P — Powertrain

Hydraulic Oil Temperature Sensor Circuit

Brand: Generic

Type: P — Powertrain

Views: UK: 17 EN: 36 RU: 25

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Page language: EN

Causes

Open or shorted sensor wiring (power, signal, or ground)
Corroded, loose, or contaminated connector
Failed hydraulic oil temperature sensor (thermistor/RTD)
Poor or missing ground at sensor or control module
Intermittent wiring damage (chafing, pinched, broken strands)
Faulty control module or reference voltage circuit

Symptoms

Transmission/driveability warning lamp (MIL) illuminated
Erratic shifting, delayed shifts, or limp-home mode
Transmission or hydraulic control faults / reduced performance
Oil temperature gauge reading erratic or pegged
Possible loss of torque management or altered shift schedule

What to check

Read/all freeze-frame and pending codes; note conditions when code set
Visually inspect sensor connector, wiring harness, and routing for damage, corrosion, or contamination
Check hydraulic oil level and condition (contamination, overheating)
Backprobe sensor signal and ground with a DVOM or scope while monitoring continuity and voltage
Measure sensor resistance across terminals at known temperatures and compare to spec
Perform wiggle test on wiring while observing live data for intermittent changes

Signal parameters

Sensor type: typically an NTC thermistor (resistance decreases as temp rises)
Typical resistance range (example): ~0.5 kΩ to 10 kΩ across -40°C to +150°C (manufacturer-specific)
Open-circuit: very high resistance or OL; Short-circuit: near 0 Ω
Typical signal voltage to control module: 0.5–4.5 V depending on temp and reference (most use a 5 V reference)
Expected behavior: smooth, monotonic change in resistance/voltage with temperature; no intermittent spikes

Diagnostic algorithm

Retrieve freeze-frame data and confirm the conditions when the code set (temp, load, speed).
Visually inspect sensor and harness for damage, corrosion, loose pins, or fluid intrusion. Repair or replace as needed.
Verify hydraulic fluid level and condition; top or replace fluid if contaminated or incorrect.
Backprobe sensor connector: measure reference voltage from module, sensor signal voltage, and ground continuity. Compare to factory specs.
With sensor removed (if specified by manufacturer), measure sensor resistance at ambient temperature and compare to expected table. If possible, heat or cool sensor and confirm resistance changes smoothly.
Check wiring continuity between sensor connector and module; check for short to power or ground. Repair broken wires, poor crimps, or corroded terminals.
If wiring and sensor test good, test module grounds and reference circuits; substitute a known-good module or bench test if available.
After repairs or component replacement, clear codes and perform a drive cycle for verification. Re-check for stored or pending codes.

Likely causes

Corroded/loose connector at sensor
Broken wire or short to ground/power in harness to sensor
Failed temperature sensor element (open/short or out-of-spec resistance)
Bad ground at sensor or ECU/module
Control module fault (less common)

Fault status

⚠️ Status

Hydraulic oil temperature sensor circuit malfunction detected — signal out of range, open, short, or intermittent. Control module may limit functionality until proper temperature input is restored.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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