AutoCodes – Generic – P1AC7

P1AC7 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 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 9,964

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

What does this mean?

What are the Possible Causes of the DTC P1AC7?

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?

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 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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Need more information on how to fix the P1AC7 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1AC7 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P1AC7 Buick — Drive Motor 1 Control Module Crankshaft Position Sensor Performance
P1AC7 Cadillac — Drive Motor 1 Control Module Crankshaft Position Sensor Performance
P1AC7 Chevrolet — Drive Motor 1 Control Module Crankshaft Position Sensor Performance
P1AC7 GMC — Drive Motor 1 Control Module Crankshaft Position Sensor Performance
P1AC7 Saturn — Drive Motor 1 Control Module Crankshaft Position Sensor Performance

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 Code

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

- Common symptoms include engine misfires, rough idling, decreased fuel efficiency, and potential stalling while driving.

2. What are the possible causes of OBDII code P1AC7 indicating an issue with the Drive Motor 1 Control Module Crankshaft Position Sensor?

- Potential causes include a faulty crankshaft position sensor, wiring issues, electrical faults, or problems with the drive motor control module.

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

- Diagnosis typically involves using a scan tool to read the code, checking the crankshaft position sensor for proper operation, and inspecting the wiring for any damage.

4. Can I continue driving with OBDII code P1AC7 triggered by the Drive Motor 1 Control Module Crankshaft Position Sensor issue?

- It is not recommended to drive with this code active, as it can lead to further engine damage or potential safety hazards on the road.

5. What are some repair tips for resolving OBDII code P1AC7 associated with the Drive Motor 1 Control Module Crankshaft Position Sensor?

- Repair tips may include replacing the faulty crankshaft position sensor, repairing any damaged wiring, or reprogramming the drive motor control module if necessary.

6. How much does it typically cost to repair OBDII code P1AC7 linked to the Drive Motor 1 Control Module Crankshaft Position Sensor?

- Repair costs can vary depending on the specific issue, but expect to pay for parts and labor, which could range from $100 to $500 or more.

7. Are there any DIY solutions for fixing OBDII code P1AC7 related to the Drive Motor 1 Control Module Crankshaft Position Sensor?

- While some basic troubleshooting like checking connections and sensor condition can be done at home, complex repairs may require professional assistance due to the sensitive nature of the components involved.

8. How urgent is it to address OBDII code P1AC7 indicating a problem with the Drive Motor 1 Control Module Crankshaft Position Sensor?

- It is advisable to address this code promptly to prevent further damage to the engine or drivability issues while operating the vehicle.

9. Can a faulty Drive Motor 1 Control Module Crankshaft Position Sensor cause other OBDII codes to trigger?

- Yes, a faulty sensor can lead to related codes like P0335 (Crankshaft Position Sensor A Circuit Malfunction) or P0336 (Crankshaft Position Sensor A Circuit Range/Performance).

10. Is it necessary to reset the OBDII system after repairing OBDII code P1AC7 associated with the Drive Motor 1 Control Module Crankshaft Position Sensor?

- Yes, it is recommended to reset the OBDII system after repairs to clear the code and ensure the issue has been successfully resolved.