P1901 – OBD-II DTC

OBD-II DTC P1901 – Transmission Transfer Case Disengaged Solenoid Short to Ground

DTC P1901 meaning

DTC P1901 refers to a diagnostic trouble code indicating a problem with the transmission transfer case disengaged solenoid. Specifically, it signifies that the solenoid has a short to ground condition. This solenoid is responsible for engaging and disengaging the transfer case, which is crucial for vehicles with four-wheel drive (4WD) or all-wheel drive (AWD) systems.

DTC P1901 symptoms

Common symptoms associated with DTC P1901 may include:

• Inability to engage or disengage the transfer case
• Warning lights on the dashboard, such as the check engine light
• Unusual noises from the transfer case area
• Transmission slipping or erratic shifting
• Reduced traction or control in slippery conditions

DTC P1901 causes

Several factors can lead to the occurrence of DTC P1901, including:

• Faulty transfer case disengaged solenoid
• Wiring issues, such as damaged or frayed wires
• Corrosion or poor connections in the electrical circuit
• Faulty transmission control module (TCM)
• Software issues in the vehicle’s control systems

DTC P1901 seriousness

DTC P1901 is considered a serious issue, particularly for vehicles that rely on the transfer case for proper operation. If left unaddressed, it can lead to:

• Inability to use 4WD or AWD features
• Increased risk of accidents due to loss of traction
• Potential damage to the transmission or transfer case

How to diagnose DTC P1901

To diagnose DTC P1901, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the P1901 code.
2. Inspect the wiring and connectors related to the transfer case disengaged solenoid for damage or corrosion.
3. Test the solenoid for proper operation using a multimeter.
4. Check the transmission control module (TCM) for any software updates or faults.
5. Perform a visual inspection of the transfer case for any signs of leaks or mechanical issues.

How to fix DTC P1901 step-by-step instructions

To fix DTC P1901, follow these step-by-step instructions:

1. Disconnect the vehicle’s battery to ensure safety while working on electrical components.
2. Inspect and repair any damaged wiring or connectors related to the transfer case disengaged solenoid.
3. Replace the transfer case disengaged solenoid if it is found to be faulty.
4. Reconnect the battery and clear the DTC using an OBD-II scanner.
5. Test drive the vehicle to ensure the issue is resolved and monitor for any reoccurrence of the code.

How to erase DTC P1901

To erase DTC P1901, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the option to clear or erase trouble codes on the scanner.
4. Confirm the action to erase the DTC.
5. Disconnect the scanner and start the vehicle to ensure the code does not return.

Recommended tools for OBD-II diagnostics

Explore our expert picks: The Best OBD2 Scanners for 2025

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.