P1891 Code - Transmission Transfer Case Contact Plate Ground Return Open Circuit
Quick Answer
P1891 indicates Transmission Transfer Case Contact Plate Ground Return Open Circuit. Common causes include Faulty Transfer Case Motor, Transfer Case Motor harness is open or shorted, Transfer Case Motor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P1891 indicates Transmission Transfer Case Contact Plate Ground Return Open Circuit.
- Common causes
- Common causes include Faulty Transfer Case Motor, Transfer Case Motor harness is open or shorted, Transfer Case Motor circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P1891 Description
What are the Possible Causes of the DTC P1891?
- Faulty Transfer Case Motor
- Transfer Case Motor harness is open or shorted
- Transfer Case Motor circuit poor electrical connection
How to Fix the DTC P1891?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P1891 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Information for Specific Makes
- P1891 Buick — Throttle Position Sensor PWM Signal Low
- P1891 Cadillac — Throttle Position Sensor PWM Signal Low
- P1891 Chevrolet — Throttle Position Sensor PWM Signal Low
- P1891 Ford — Transmission Transfer Case Contact Plate Ground Return Open Circuit
- P1891 GMC — Throttle Position Sensor PWM Signal Low
- P1891 Honda — Problem in Start Clutch System
Frequently Asked Questions about P1891 Code
1. What does OBDII code P1891 mean?
Code P1891 indicates an issue with the transmission transfer case contact plate ground return circuit, which means the ground return for the transfer case contact plate is open or disconnected.
2. What are the common symptoms of code P1891?
Symptoms may include transfer case malfunctions, inability to shift into certain drive modes (e.g., 4WD or AWD), illuminated check engine light, and potential drivetrain performance issues.
3. What causes the P1891 code to appear?
Common causes include damaged or corroded wiring, a loose or broken ground connection, faulty contact plate, or issues with the transfer case control module.
4. Can I drive my vehicle with code P1891?
While the vehicle may still be drivable, it could experience issues with mode shifting or drivetrain functionality, particularly in off-road or slippery conditions. Prompt diagnosis and repair are recommended.
5. How do I diagnose a P1891 code?
Start by inspecting the wiring and ground connections for the transfer case contact plate. Use a multimeter to check for continuity and ensure there is no resistance in the ground return circuit.
6. What tools are needed to fix a P1891 code?
Basic tools include a multimeter for electrical testing, wiring diagrams for reference, and potentially a scan tool to clear the code after repairs.
7. How do I fix the P1891 code?
Repairs may involve cleaning or reconnecting ground wires, replacing damaged wiring, or replacing the transfer case contact plate if it’s determined to be faulty.
8. Can a faulty transfer case control module cause the P1891 code?
Yes, if the control module is malfunctioning, it may not properly manage the ground return circuit, leading to the P1891 code.
9. How much does it cost to fix a P1891 code?
The cost varies depending on the root cause. Simple repairs like fixing ground connections may cost under $100, while replacing a contact plate or control module could cost several hundred dollars.
10. Will clearing the P1891 code with a scan tool fix the problem?
Clearing the code will not fix the underlying issue. The root cause of the open circuit must be repaired to prevent the code from returning.
Discuss the causes and fixes for P1891 OBDII Code
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