AutoCodes – GMC – P1656 GMC

P1656 GMC Code - Intake Camshaft Actuator Control Circuit

Quick Answer

The DTC P1656 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit diagnostic monitors the operation of the CMP actuator system. Common causes include Faulty Intake Camshaft Position (CMP) Actuator Solenoid, Intake Camshaft Position (CMP) Actuator Solenoid harness is open or shorted, Intake Camshaft Position (CMP) Actuator Solenoid 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: P1656 GMC indicates Intake Camshaft Actuator Control Circuit.
Common causes: Common causes include Faulty Intake Camshaft Position (CMP) Actuator Solenoid, Intake Camshaft Position (CMP) Actuator Solenoid harness is open or shorted, Intake Camshaft Position (CMP) Actuator Solenoid 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 10,734

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 06, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
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Code P1656 GMC Description

The DTC P1656 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit diagnostic monitors the operation of the CMP actuator system. The CMP actuator system enables the Powertrain control Module (PCM) to change the camshaft timing when the engine is running. THE CMP actuator solenoid valve control the oil flow that applies the pressure to advance or retard the camshaft. The PCM provides a Pulse Width Modulated (PWM) signal for control of the CMP actuator solenoid.

OBDII Code P1656 GMC - Intake Camshaft Actuator Control Circuit - AutoCodes.com — P1656 GMC Code - Intake Camshaft Actuator Control Circuit

What does this mean?

What are the Possible Causes of the DTC P1656 GMC?

Faulty Intake Camshaft Position (CMP) Actuator Solenoid
Intake Camshaft Position (CMP) Actuator Solenoid harness is open or shorted
Intake Camshaft Position (CMP) Actuator Solenoid circuit poor electrical connection

How to Fix the DTC P1656 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 P1656 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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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.