AutoCodes – GMC – P034A GMC

P034A GMC Code - Crankshaft Position Sensor Engine Start Position Incorrect

Quick Answer

The Engine Control Module (ECM) monitors the speed and the direction of rotation of the crankshaft during an autostop event and memorizes the crankshaft angle at which the engine stopped to be able to start the engine quicker. Common causes include Faulty Crankshaft Position Sensor, Crankshaft Position Sensor harness is open or shorted, Crankshaft 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: P034A GMC indicates Crankshaft Position Sensor Engine Start Position Incorrect.
Common causes: Common causes include Faulty Crankshaft Position Sensor, Crankshaft Position Sensor harness is open or shorted, Crankshaft 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.

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Code Popularity 359

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 Sep 23, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P034A GMC Description

The Engine Control Module (ECM) monitors the speed and the direction of rotation of the crankshaft during an autostop event and memorizes the crankshaft angle at which the engine stopped to be able to start the engine quicker. The Diagnostic Trouble Code (DTC) will be set when the difference between the memorized and actual crankshaft position was greater than 1 reluctor ring teeth during 2 autostart events in one ignition cycle.

OBDII Code P034A GMC - Crankshaft Position Sensor Engine Start Position Incorrect - AutoCodes.com — P034A GMC Code - Crankshaft Position Sensor Engine Start Position Incorrect

What does this mean?

What are the Possible Causes of the DTC P034A GMC?

Faulty Crankshaft Position Sensor
Crankshaft Position Sensor harness is open or shorted
Crankshaft Position Sensor circuit poor electrical connection

How to Fix the DTC P034A 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 P034A 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.

Need more information about the P034A GMC code?

Need more information on how to fix the P034A GMC code? Get Access to Factory Service Manuals

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Information for Specific GMC Models

P034A 2014 GMC Sierra — Crankshaft Position Sensor Engine Start Position Incorrect
P034A 2015 GMC Sierra — Crankshaft Position Sensor Engine Start Position Incorrect
P034A 2016 GMC Sierra — Crankshaft Position Sensor Engine Start Position Incorrect
P034A 2017 GMC Sierra — Crankshaft Position Sensor Engine Start Position Incorrect
P034A 2018 GMC Sierra — Crankshaft Position Sensor Engine Start Position Incorrect

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 P034A GMC Code

What does the OBDII code P034A mean for a GMC vehicle?

The P034A code indicates that the crankshaft position sensor has detected an incorrect engine start position, causing potential timing or synchronization issues.

What are the common symptoms of the P034A code?

Symptoms may include difficulty starting the engine, rough idling, reduced engine performance, engine stalling, or an illuminated check engine light.

What causes the P034A code to appear?

Common causes include a faulty crankshaft position sensor, damaged wiring or connectors, issues with the timing chain or belt, or a malfunctioning engine control module (ECM).

Can I continue driving with the P034A code?

It is not recommended to drive with this code active, as it can lead to poor engine performance, stalling, or further damage to engine components.

How can I diagnose the P034A code?

Start by inspecting the crankshaft position sensor, its wiring, and connectors for damage. Use a scan tool to monitor live data and check for timing-related issues.

How do I fix the P034A code on my GMC?

Repairs may include replacing the crankshaft position sensor, fixing damaged wiring, re-timing the engine, or updating/replacing the ECM if necessary.

How much does it cost to repair the P034A code?

Repair costs vary but typically range from $100 to $300 for a crankshaft position sensor replacement, depending on labor and parts pricing.

Can a dead battery cause the P034A code?

A weak or dead battery is unlikely to directly cause this code, but voltage issues can affect the ECM and sensor functionality, potentially contributing to the problem.

Do I need to reprogram the ECM after fixing the P034A code?

In most cases, reprogramming is not required, but clearing the code with a scan tool and performing a test drive are recommended to ensure the issue is resolved.

What other codes might appear with P034A?

Codes related to the camshaft position sensor (e.g., P0340) or timing issues may appear alongside P034A, indicating a broader synchronization problem.