P1891 GMC Code - Throttle Position Sensor PWM Signal Low
Quick Answer
P1891 GMC indicates Throttle Position Sensor PWM Signal Low. Common causes include Faulty Throttle Position Sensor, Throttle Position Sensor harness is open or shorted, Throttle Position Sensor 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 GMC indicates Throttle Position Sensor PWM Signal Low.
- Common causes
- Common causes include Faulty Throttle Position Sensor, Throttle Position Sensor harness is open or shorted, Throttle Position Sensor 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 GMC Description
What are the Possible Causes of the DTC P1891 GMC?
- Faulty Throttle Position Sensor
- Throttle Position Sensor harness is open or shorted
- Throttle Position Sensor circuit poor electrical connection
How to Fix the DTC P1891 GMC?
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 GMC 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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Frequently Asked Questions about P1891 GMC Code
1. What does the OBDII code P1891 mean for a GMC vehicle?
P1891 indicates that the Throttle Position Sensor (TPS) PWM signal is reading as too low, suggesting a potential issue with the sensor or its associated circuitry.
2. What are the common symptoms of code P1891 on a GMC?
Symptoms may include poor engine performance, hesitation during acceleration, stalling, erratic idling, or the illumination of the check engine light.
3. What causes the P1891 code to appear on a GMC?
Common causes include a faulty throttle position sensor, damaged wiring or connectors, corrosion in the TPS circuit, or issues with the powertrain control module (PCM).
4. Can I drive my GMC with the P1891 code active?
Driving with this code is not recommended as it can lead to poor throttle response or unsafe driving conditions. Address the issue promptly to prevent further problems.
5. How do I diagnose the P1891 code on a GMC?
Start by inspecting the TPS and its wiring for visible damage or corrosion. Use a multimeter to check for proper voltage and continuity in the TPS circuit. A scan tool can also monitor the sensor's signal output.
6. How is the P1891 code fixed on a GMC?
Repairs typically involve replacing a faulty throttle position sensor, repairing damaged wiring or connectors, cleaning corroded connections, or reprogramming the PCM if necessary.
7. Is a throttle position sensor expensive to replace on a GMC?
The cost varies depending on the vehicle model, but TPS replacement typically ranges from $100 to $300, including parts and labor.
8. Can a dirty throttle body cause the P1891 code on a GMC?
While a dirty throttle body is not a direct cause, it can impact the TPS readings. Cleaning the throttle body may help in some cases but won’t resolve a faulty TPS or wiring issue.
9. Will disconnecting the battery clear the P1891 code on a GMC?
Disconnecting the battery may temporarily clear the code, but the underlying issue must be fixed to prevent the code from returning.
10. How can I prevent the P1891 code from occurring again on my GMC?
Regular maintenance, such as inspecting the throttle body and TPS wiring for wear or dirt, can help reduce the likelihood of this code reappearing.
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