AutoCodes – Generic – C1100

C1100 Code - ABS Pump Switch Circuit Failure

Quick Answer

When the driver stops too fast, and one or more wheels begin to lock up, the ABS system takes over. Common causes include ABS Pump Switch / Wiring intermittently open/shorted, Faulty / intermittent connection at the Anti-Lock Brake Control Module (ABCM or EBCM), Faulty Anti-Lock Brake Control Module. 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: C1100 indicates ABS Pump Switch Circuit Failure.
Common causes: Common causes include ABS Pump Switch / Wiring intermittently open/shorted, Faulty / intermittent connection at the Anti-Lock Brake Control Module (ABCM or EBCM), Faulty Anti-Lock Brake Control Module.
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 37,191

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 Aug 13, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code C1100 Description

When the driver stops too fast, and one or more wheels begin to lock up, the ABS system takes over. It sees the wheel or wheels slowing down too rapidly by way of wheel speed sensors. When this happens, it shuts off brake fluid to the wheel with the inlet valve/coil, and releases the pressure with an outlet valve/coil. The ABS pump is what replenishes the brake fluid, and the ABS Pump Switch informs the ABS control module when the pump is running/turns on the pump depending upon manufacturer’s application. The ABS pump switch is typically found on vehicles with 4 Wheel Anti-Lock Brakes. The ABS system checks to be sure that the switch electrical circuit is ok every time the key is turned on and the ABS module is powered up. If there is a problem with the wiring to the switch or the switch itself, the ABS module will communicate over a data bus to the instrument cluster to turn on the amber Anti-Lock Light and the Red Brake Warning Light, and ABS will be disabled. In this case, the module has checked the ABS pump switch wiring and found the circuit has an electrical problem. This sets a C1100 in memory.

OBDII Code C1100 - ABS Pump Switch Circuit Failure - AutoCodes.com — C1100 Code - ABS Pump Switch Circuit Failure

What does this mean?

What are the Possible Causes of the DTC C1100?

ABS Pump Switch / Wiring intermittently open/shorted
Faulty / intermittent connection at the Anti-Lock Brake Control Module (ABCM or EBCM)
Faulty Anti-Lock Brake Control Module

How to Fix the DTC C1100?

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

This is typically an electrical wiring connection issue the ABS Control Module monitors for the manufacturer.
It can occur if: The pressure switch/wiring itself is bad.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C1100 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 C1100 code?

Need more information on how to fix the C1100 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C1100 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

C1100 Buick — Brake Booster Vacuum Sensor Performance
C1100 Cadillac — Brake Booster Vacuum Sensor Performance
C1100 Chevrolet — Brake Booster Vacuum Sensor Performance
C1100 GMC — Brake Booster Vacuum Sensor Performance
C1100 Hummer — Brake Booster Vacuum Sensor Performance
C1100 Pontiac — Brake Booster Vacuum Sensor Performance
C1100 Saturn — Brake Booster Vacuum 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 C1100 Code

1. What are the common symptoms of OBDII code C1100 ABS Pump Switch Circuit Failure?

The common symptoms of this code include the ABS warning light illuminating on the dashboard, loss of ABS functionality, and potential issues with the vehicle's braking system.

2. What are some possible causes of OBDII code C1100 ABS Pump Switch Circuit Failure?

Potential causes of this code include a faulty ABS pump switch, damaged wiring or connectors in the ABS system, or a malfunctioning ABS control module.

3. How can I diagnose OBDII code C1100 ABS Pump Switch Circuit Failure?

Diagnosing this code typically involves using a diagnostic scanner to retrieve the specific trouble codes, inspecting the ABS system components for visible damage, and testing the ABS pump switch and related circuits for proper functionality.

4. Can I drive my vehicle with OBDII code C1100 ABS Pump Switch Circuit Failure?

It is not recommended to drive your vehicle with this code present, as it may compromise the effectiveness of the ABS system and impact braking performance. It is advisable to address the issue promptly.

5. How can I repair OBDII code C1100 ABS Pump Switch Circuit Failure?

Repairing this code may involve replacing the faulty ABS pump switch, repairing damaged wiring or connectors, or addressing any issues with the ABS control module. It is recommended to consult a qualified mechanic for proper diagnosis and repair.

6. Is OBDII code C1100 ABS Pump Switch Circuit Failure a serious issue?

While this code may not cause immediate safety concerns, it can affect the functionality of the ABS system, which is crucial for safe driving. It is important to address this issue to ensure optimal vehicle performance and safety.

7. Can resetting the OBDII code C1100 ABS Pump Switch Circuit Failure resolve the issue?

Resetting the code may temporarily turn off the warning light, but it will not fix the underlying problem causing the ABS Pump Switch Circuit Failure. It is essential to diagnose and repair the issue to prevent further complications.

8. How long does it take to repair OBDII code C1100 ABS Pump Switch Circuit Failure?

The repair time for this code can vary depending on the specific cause of the issue and the extent of the repairs needed. It is best to consult a professional mechanic for an accurate assessment of the repair timeline.

9. Will OBDII code C1100 ABS Pump Switch Circuit Failure cause my vehicle to fail an emissions test?

While this code is related to the ABS system rather than emissions, it is still important to address it to ensure the overall functionality and safety of your vehicle. It should not directly impact the emissions test results.

10. Can a DIY enthusiast fix OBDII code C1100 ABS Pump Switch Circuit Failure at home?

While some basic troubleshooting steps can be done at home, diagnosing and repairing this code often requires specialized tools and expertise. It is recommended to seek professional help to accurately diagnose and fix the issue.