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P1AC7 Buick Code - Drive Motor 1 Control Module Crankshaft Position Sensor Performance

Quick Answer

The crankshaft position (CKP) sensor circuits consist of an Engine Control Module (ECM) supplied 5-volt reference circuit, low reference circuit and an output signal circuit. Common causes include Faulty Drive Motor Generator Power Inverter Control Module (PIM), Drive Motor Generator Power Inverter Control Module (PIM) harness is open or shorted, Drive Motor Generator Power Inverter Control Module (PIM) 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: P1AC7 Buick indicates Drive Motor 1 Control Module Crankshaft Position Sensor Performance.
Common causes: Common causes include Faulty Drive Motor Generator Power Inverter Control Module (PIM), Drive Motor Generator Power Inverter Control Module (PIM) harness is open or shorted, Drive Motor Generator Power Inverter Control Module (PIM) 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.

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Code Popularity 836

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Mar 01, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P1AC7 Buick Description

The crankshaft position (CKP) sensor circuits consist of an Engine Control Module (ECM) supplied 5-volt reference circuit, low reference circuit and an output signal circuit. The CKP sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 58-tooth reluctor wheel on the crankshaft. Each tooth on the reluctor wheel is spaced at 60-tooth spacing, with 2 missing teeth for the reference gap. The CKP sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the CKP sensor output depends on the velocity of the crankshaft. The CKP sensor sends a digital signal, which represents an image of the crankshaft reluctor wheel, to the ECM as each tooth on the wheel rotates past the CKP sensor. The ECM uses each CKP signal pulse to determine crankshaft speed and decodes the crankshaft reluctor wheel reference gap to identify crankshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The ECM also uses CKP sensor output information to determine the crankshaft relative position to the camshaft, to detect cylinder misfire, and to control the CMP actuator if equipped.
Motor Control Module (MCM) 1 is also connected to the CKP sensor signal and low reference circuits. The MCM uses the CKP sensor output information to determine engine crankshaft position to aid in smooth engine Auto-starts.

OBDII Code P1AC7 Buick - Drive Motor 1 Control Module Crankshaft Position Sensor Performance - AutoCodes.com — P1AC7 Buick Code - Drive Motor 1 Control Module Crankshaft Position Sensor Performance

What does this mean?

What are the Possible Causes of the DTC P1AC7 Buick?

Faulty Drive Motor Generator Power Inverter Control Module (PIM)
Drive Motor Generator Power Inverter Control Module (PIM) harness is open or shorted
Drive Motor Generator Power Inverter Control Module (PIM) circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P1AC7 Buick?

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 does this mean?

Code Tech Notes

If codes P0335 or P0336 are set, diagnose them prior to diagnosing this code.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1AC7 Buick 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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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1AC7 Buick Code

1. What are the common symptoms of OBDII code P1AC7 in a Buick related to the Drive Motor 1 Control Module Crankshaft Position Sensor performance?

The common symptoms include engine stalling, rough idling, poor acceleration, and potential difficulty starting the vehicle.

2. What are the possible causes of OBDII code P1AC7 in a Buick related to the Drive Motor 1 Control Module Crankshaft Position Sensor performance?

Potential causes can include a faulty crankshaft position sensor, wiring issues, a malfunctioning drive motor control module, or software problems.

3. How can I diagnose the OBDII code P1AC7 in a Buick related to the Drive Motor 1 Control Module Crankshaft Position Sensor performance?

Diagnosis typically involves using a scan tool to retrieve the fault codes, testing the crankshaft position sensor for proper operation, checking the wiring for any damage, and inspecting the drive motor control module.

4. What are some repair tips for fixing OBDII code P1AC7 in a Buick related to the Drive Motor 1 Control Module Crankshaft Position Sensor performance?

Repair tips may include replacing the faulty crankshaft position sensor, repairing or replacing damaged wiring, reprogramming the drive motor control module if necessary, and clearing the fault codes.

5. Can I continue driving my Buick with OBDII code P1AC7 related to the Drive Motor 1 Control Module Crankshaft Position Sensor performance?

It is not recommended to drive the vehicle with this issue as it can lead to more severe problems and potentially cause further damage to the engine or drive motor components.

6. How much does it typically cost to repair OBDII code P1AC7 in a Buick related to the Drive Motor 1 Control Module Crankshaft Position Sensor performance?

The cost of repair can vary depending on the specific cause of the issue, but it may range from $100 to $500 or more, including parts and labor.

7. Is it possible to reset the OBDII code P1AC7 in a Buick related to the Drive Motor 1 Control Module Crankshaft Position Sensor performance without making any repairs?

While clearing the fault code may temporarily turn off the check engine light, it is essential to address the underlying issue to prevent further problems.

8. How long does it take to repair OBDII code P1AC7 in a Buick related to the Drive Motor 1 Control Module Crankshaft Position Sensor performance?

The repair time can vary depending on the complexity of the issue and the availability of parts, but it typically takes a few hours to a full day to diagnose and fix the problem.

9. Can a DIY enthusiast without much experience attempt to fix OBDII code P1AC7 in a Buick related to the Drive Motor 1 Control Module Crankshaft Position Sensor performance?

While some basic troubleshooting steps can be performed by DIY enthusiasts, it is recommended to consult a professional mechanic for a proper diagnosis and repair to ensure the issue is resolved correctly.

10. Are there any recalls or technical service bulletins related to OBDII code P1AC7 in Buick vehicles concerning Drive Motor 1 Control Module Crankshaft Position Sensor performance?

It is advisable to check with the manufacturer or a certified dealership for any relevant recalls or technical service bulletins that may address this specific OBDII code and related issues in Buick vehicles.