P2741

Code

Generic P — Powertrain

Transmission Fluid Temperature Sensor B Circuit Range/Performance

Brand: Generic

Type: P — Powertrain

Views: UK: 31 EN: 51 RU: 32

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Page language: EN

Causes

Open or short in Transmission Fluid Temperature Sensor B wiring
Corroded, loose, or damaged sensor connector
Failed or out-of-spec transmission fluid temperature sensor (Sensor B)
Poor ground or reference voltage to the sensor circuit
Contaminated or incorrect transmission fluid affecting sensor reading
Faulty TCM/PCM or software/calibration issue

Symptoms

Malfunction indicator lamp (MIL) / Check Engine Light illuminated
Transmission may shift abnormally or go into limp/limitation mode
Erratic or no transmission fluid temperature gauge/scan tool reading for Sensor B
Delayed engagement, torque converter lockup issues, or degraded drivability
Possible storage of additional transmission-related fault codes

What to check

Read freeze frame and live data with a capable scan tool; compare TFT Sensor B reading to Sensor A and ambient/engine coolant temps
Visual inspection of sensor connector, wiring harness and transmission grounds for damage, corrosion or looseness
Backprobe sensor connector and confirm reference voltage and ground continuity from module
Measure sensor resistance and/or voltage at known temperatures and compare to specification (manufacturer data)
Wiggle-test harness while monitoring live data to spot intermittent faults
Inspect transmission fluid level and condition; verify correct fluid type

Signal parameters

Sensor type: typically a thermistor (resistance changes with temperature)
Typical signal behaviour: monotonic change with temperature (voltage or resistance should increase or decrease steadily as fluid warms)
Expected voltages (generic): about 0.5–4.5 V signal range depending on design — check vehicle-specific spec
Expected resistance (generic): varies by sensor and temp; may range from a few hundred ohms to several kiloohms across operating temperatures
Reference: presence of stable 5 V (or vehicle reference voltage) and good ground to the sensor circuit

Diagnostic algorithm

Verify and record the code(s) and freeze-frame data. Note whether Sensor A also has faults.
Inspect connectors and wiring for obvious damage, corrosion, pin push-out, or contamination. Repair as needed.
With ignition on, backprobe the sensor connector: confirm reference voltage, signal voltage, and ground. Compare to manufacturer specs.
Measure sensor resistance at ambient temperature and while warming (use hot water or run vehicle to warm transmission) and compare to spec curve. If resistance does not change predictably, suspect sensor.
Perform continuity checks from sensor connector to the PCM/TCM pins to rule out opens/shorts. Repair harness faults if found.
If live data shows erratic values only when harness is moved, repair or replace wiring/harness and retest.
If wiring and connector are good but sensor readings remain out of range, replace TFT Sensor B and clear codes.
After repairs, clear codes and perform a road test or heat-soak test to confirm proper sensor behavior and that the DTC does not return.
If issue persists with good sensor and harness, consider module input fault; verify module ground(s) and software level, and consult manufacturer resources before replacing module.

Likely causes

Damaged or corroded connector at the sensor
Broken wire or short to battery/ground in sensor harness
Failed TFT Sensor B thermistor element
Missing or poor ground at transmission/PCM
Faulty module or need for module reflash (less common)

Fault status

⚠️ Status

Transmission Fluid Temperature Sensor B Circuit Range/Performance — the control module detected a sensor B signal outside the expected range or not varying correctly with temperature. Could be caused by sensor, wiring, connector, reference/ground, or module issues.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours