AutoCodes – Generic – P263B

P263B Code - Malfunction Indicator Lamp Control Circuit High Voltage

Quick Answer

The Malfunction Indicator Lamp (MIL) illuminates to inform the driver that an emission system fault has occurred, and the powertrain control system requires service. Common causes include Faulty Malfunction Indicator Lamp Bulb, Malfunction Indicator Lamp Bulb harness is open or shorted, Malfunction Indicator Lamp Bulb 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: P263B indicates Malfunction Indicator Lamp Control Circuit High Voltage.
Common causes: Common causes include Faulty Malfunction Indicator Lamp Bulb, Malfunction Indicator Lamp Bulb harness is open or shorted, Malfunction Indicator Lamp Bulb 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 1,170

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 18, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P263B Description

The Malfunction Indicator Lamp (MIL) illuminates to inform the driver that an emission system fault has occurred, and the powertrain control system requires service. Ignition voltage is supplied directly to the MIL. The Engine Control Module (ECM) turns the MIL ON by grounding the MIL control circuit when the emission system fault occurs. Under normal operating conditions, the MIL should be ON only when the ignition is ON, and the engine is OFF. The Diagnostic Trouble Code (DTC) will be set when the ECM detects high voltage on the MIL control circuit during the driver ON state. This indicates a shorted to voltage MIL control circuit.

OBDII Code P263B - Malfunction Indicator Lamp Control Circuit High Voltage - AutoCodes.com — P263B Code - Malfunction Indicator Lamp Control Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P263B?

Faulty Malfunction Indicator Lamp Bulb
Malfunction Indicator Lamp Bulb harness is open or shorted
Malfunction Indicator Lamp Bulb circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P263B?

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 the condition is intermittent, move the related harnesses and connectors while monitoring the scan tool MIL control circuit status parameters. Perform this test with the ignition ON and the engine OFF, and with the engine running. The MIL control circuit status parameters change from OK or Not Run to Malfunction if there is a condition with a circuit or a connection.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P263B 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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Information for Specific Makes

P263B Buick — Malfunction Indicator Lamp Control Circuit High Voltage
P263B Cadillac — Malfunction Indicator Lamp Control Circuit High Voltage
P263B Chevrolet — Malfunction Indicator Lamp Control Circuit High Voltage
P263B GMC — Malfunction Indicator Lamp Control Circuit High Voltage

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.