AutoCodes – GMC – P1218 GMC

P1218 GMC Code - Injection Pump Calibration Circuit

Quick Answer

The Powertrain Control Module (PCM) uses a calibrated resistor internally in the Injection Pump to determine fuel rates. Common causes include Powertrain Control Module (PCM) currently does not have a resistor value, Powertrain Control Module (PCM) is unable to read resistor value. 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: P1218 GMC indicates Injection Pump Calibration Circuit.
Common causes: Common causes include Powertrain Control Module (PCM) currently does not have a resistor value, Powertrain Control Module (PCM) is unable to read resistor value.
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 6,816

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 14, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P1218 GMC Description

The Powertrain Control Module (PCM) uses a calibrated resistor internally in the Injection Pump to determine fuel rates. the resistor value is stored in the PCM memory. If the PCM memory has been disturbed or replaced the PCM will relearn the resistor value on the next ignition cycle. The code is set when the key ON or engine running and PCM does not detects a correct current valid resistor value, or it determined that it was unable to read the current resistor value.

OBDII Code P1218 GMC - Injection Pump Calibration Circuit - AutoCodes.com — P1218 GMC Code - Injection Pump Calibration Circuit

What does this mean?

What are the Possible Causes of the DTC P1218 GMC?

Powertrain Control Module (PCM) currently does not have a resistor value
Powertrain Control Module (PCM) is unable to read resistor value

How to Fix the DTC P1218 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 does this mean?

Code Tech Notes

The P1218 code usually sets when the resistor is missing out of the PMD or the system has been disturbed and the ECU is re-learning the resistor value. Most of the times the problem is the missing resistor. Cycling the key many times will relearn the resistor value.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1218 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.

Frequently Asked Questions about P1218 GMC Code

1. What does the OBDII code P1218 mean for GMC vehicles?

P1218 indicates an issue with the injection pump calibration circuit, usually related to the fuel delivery system.

2. What are the common symptoms of code P1218 in a GMC?

Symptoms may include engine misfires, rough idling, poor acceleration, reduced fuel efficiency, and the Check Engine Light being illuminated.

3. What causes code P1218 in GMC vehicles?

Common causes include a malfunctioning injection pump, wiring issues in the calibration circuit, or a failed pump control module.

4. Can driving with code P1218 damage my GMC vehicle?

Yes, prolonged driving with this code can cause engine performance issues and potentially damage the injection system or other engine components.

5. How is code P1218 diagnosed in GMC vehicles?

Technicians typically use a scan tool to confirm the code, inspect the injection pump and associated wiring, and test the calibration circuit for faults.

6. How can I fix code P1218 on my GMC?

Repairs may involve replacing or recalibrating the injection pump, repairing damaged wiring, or replacing the pump control module.

7. Is code P1218 specific to diesel engines in GMC vehicles?

Yes, this code is commonly associated with GMC diesel engines equipped with an electronic injection pump.

8. Does code P1218 require a professional mechanic for repairs?

Due to the complexity of the injection system, it's recommended to seek professional help for diagnosing and repairing this code.

9. How much does it cost to fix code P1218 in a GMC?

Repair costs can vary widely depending on the severity of the issue, but injection pump replacement can range between $1,000 and $2,500, including labor.

10. Can a faulty injection pump calibration circuit affect fuel economy?

Yes, a malfunctioning calibration circuit can lead to improper fuel delivery, negatively impacting fuel efficiency.