P2B2E

Code

Generic P — Powertrain

Engine Coolant Temperature Sensor 5 Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 23 EN: 85 RU: 54

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or shorted wiring on ECT sensor 5 circuit
Corroded or disconnected sensor connector
Faulty ECT sensor 5 (internal short or failed thermistor)
Short to battery/ignition voltage on the signal or reference circuit
Poor PCM ground or power supply
PCM internal fault (less common)

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Incorrect coolant temperature reading on scan tool (very high or pegged)
Poor cold/hot idle or drivability issues due to incorrect fuel/idle control
Cooling fan operation incorrect (runs constantly or not when expected)
Possible hard start or increased emissions

What to check

Read and record freeze frame and live data for ECT sensor 5 with a scan tool
Check for additional related DTCs (power, ground, other coolant sensor codes)
Visually inspect sensor 5 connector and wiring for damage, corrosion, or loose pins
Wiggle harness while monitoring live data to look for intermittent changes
Measure reference voltage and ground at the sensor connector with key ON
Measure signal voltage and/or sensor resistance and compare to expected range

Signal parameters

Typical reference voltage: ~5.0 V (verify OEM spec)
Sensor type: usually NTC thermistor (resistance decreases as temperature rises)
Typical signal voltage range: ~0.5–4.5 V depending on temperature (vehicle-specific)
Example resistance: ~2–5 kΩ at ~20–25 °C, falling to a few hundred ohms at operating temp (values vary by sensor)
Fault indicators: signal stuck near reference voltage (~5 V) or open circuit (>50 kΩ) indicates high/open; very low voltage (

Diagnostic algorithm

Retrieve freeze frame and live data. Note ECT 5 sensor value, engine temp, ignition state, and any other stored codes.
Visually inspect the sensor 5 connector, wiring harness, and nearby components for damage, corrosion, or heat damage. Repair visible issues.
With key ON (engine OFF), backprobe sensor connector: verify reference voltage (typically ~5 V) to the sensor reference pin and a good ground on the ground pin.
Measure the signal voltage at the sensor with key ON and engine cold, then again when warmed if safe. Compare to expected behavior (voltage should change with temperature).
Remove sensor and measure its resistance across the sensor terminals at a known temperature (compare to manufacturer chart or expected thermistor behavior).
If signal is high but sensor resistance is normal, check wiring for short to battery voltage using an ohmmeter/voltmeter between signal wire and battery positive with ignition off.
If open or short in harness suspected, perform continuity tests between sensor and PCM connector, check for shorts to power or ground, and inspect intermediate connectors/grounds.
If wiring and connector are good and sensor resistance is out of spec, replace ECT sensor 5. If new sensor shows same fault, verify PCM power/ground and re-test.
If all wiring, power/ground, and sensor test good but code persists, consider PCM diagnosis or replacement per manufacturer guidance.
After repairs, clear codes and perform a road/drive cycle while monitoring live data to confirm the fault does not return.

Likely causes

Broken or pinched harness between sensor and PCM
Water intrusion/corrosion at sensor connector causing high resistance or intermittent contact
ECT sensor 5 internally shorted to supply voltage
Aftermarket component or recent repair disturbed wiring or connector
Damaged insulation contacting battery voltage causing a high signal reading

Fault status

⚠️ Status

Engine Coolant Temperature Sensor 5 Circuit High — PCM detected high/open/over-voltage condition on ECT sensor 5 circuit. MIL on and freeze frame data stored.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours