P0D62

Code

Generic P — Powertrain

Hybrid/EV Battery Pack Cooling Fan 2 Sense Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 18 EN: 29 RU: 23

AI status

Completed

ready

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Page language: EN

Causes

Open or shorted wiring harness (short to battery voltage) on fan 2 sense circuit
Corroded, bent, or damaged connector pins at fan motor or controller
Failed fan motor internal sensor or tachometer (stuck output)
Poor or missing ground or reference voltage at control module
Control module (HV battery ECU or BMS) internal fault or faulty input circuit
Aftermarket modifications or water/contamination ingress into fan assembly

Symptoms

Battery thermal management warning message or reduced hybrid system performance
Cooling fan 2 may not be monitored correctly (fan speed readout abnormal or missing)
Cooling fan may not run when commanded, or may run continuously
Possible illuminated warning lamp related to hybrid/battery cooling
Possible increased battery temperature under load or after extended operation

What to check

Read/record freeze frame and live data with a scan tool: fan 2 speed (rpm or duty/frequency) and compare to fan 1
Visually inspect fan 2 connector and harness for damage, corrosion, pin pushed out, or water intrusion
Inspect routing for chafing points and proximity to high-voltage lines or moving parts
Check for related diagnostic trouble codes for fans, cooling system, or BMS
Attempt to command fan 2 ON/OFF with a factory scan tool and observe response
Measure voltage at the fan 2 sense pin with respect to chassis ground while fan is OFF and while commanded ON

Signal parameters

Type: tachometer/speed sense circuit (pulsed or open-collector output) reported as voltage/frequency to ECU
Expected idle/off: near 0 V or no pulses (circuit not driven)
Expected running: pulsed signal with voltage swings referenced to ECU pull-up (typical pulse levels 0–5 V or 0–12 V depending on vehicle design) and frequency proportional to fan RPM
Fault condition: 'Sense Circuit High' usually means the sense line is held at a higher than expected voltage (e.g., stuck near battery/ignition voltage or ECU pull-up threshold) or constant high level instead of pulsed

Diagnostic algorithm

Use scan tool to confirm P0D62 is current and record related codes and live data for fan 2 speed. Note freeze-frame conditions.
Visually inspect fan 2 connector, harness and fan assembly for damage, corrosion, water, or melted insulation. Repair any obvious damage.
With ignition/key ON (follow manufacturer safety for HV systems), backprobe the fan 2 sense pin and measure voltage with fan OFF and while commanding fan ON. Compare to expected behavior (OFF ≈ 0 V/no pulses, ON = pulsed signal).
If the sense line is held high (near battery/ignition voltage) when it should be low or pulsed, disconnect the fan 2 connector and measure the harness side: if the high voltage remains at the module/ harness side, suspect a module or harness short; if the voltage drops, suspect the fan assembly.
Check continuity from the fan 2 sense pin back to the control module; check for shorts to B+ and to ground. Repair harness faults as needed.
Swap or command-comparison: if available and safe, compare fan 2 readings with fan 1 by commanding each on. If fan 2 shows no pulses but fan 1 does, suspect fan 2 assembly.
If wiring and fan assembly test OK, inspect/replace the battery ECU/BMS connector or the ECU input circuit only after verifying all harness and component checks. Reprogram or replace ECU only as a last step.
Clear codes, perform function test and road/operational test to verify proper cooling fan 2 sensing and restoration of normal thermal management operation.

Likely causes

Short to B+ on the fan 2 sense wire (wiring abrasion or terminal pushed out)
Failed fan assembly where the tach output is stuck at high voltage
Corrosion or poor pin contact at the fan connector
Faulty battery pack ECU input or intermittent connector connection

Fault status

⚠️ Status

Battery pack cooling fan 2 speed/sense circuit voltage is higher than expected. Cooling fan 2 cannot be reliably monitored. Inspect wiring, connectors, and fan assembly for shorts or faults.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours

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