P1901

What does P1901 mean?

P-code P1901 means "Transmission Transfer Case Disengaged Solenoid Short to Ground". It is a manufacturer-specific diagnostic trouble code (DTC) in the transmission. The circuit has a short to ground, meaning an unintended path to chassis ground exists in the transmission transfer case disengaged solenoid short to ground wiring. This warning should be addressed within the next few days to avoid further damage. This code applies to OBD-II compliant electric and hybrid vehicles.

Possible Causes

• Chafed or pinched wire contacting the vehicle chassis or ground plane
• Corroded connector allowing moisture to create a ground path
• Internally shorted sensor or actuator
• Damaged wiring insulation caused by heat, abrasion, or rodent damage

Recommended Actions

1. 1 Avoid aggressive driving and schedule a diagnostic appointment within the next 1–3 days
2. 2 Scan for all DTCs with an OBD-II scanner — note any related codes stored alongside P1901
3. 3 Inspect wiring harness for chafed insulation, pinched wires, or contact with metal surfaces
4. 4 Measure voltage/resistance at the connector with the harness disconnected to locate the short
5. 5 Clear the DTC, road-test the vehicle, and re-scan to confirm whether the fault returns
6. 6 If the fault persists after inspection and clearing, consult an EV-certified technician for component replacement

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