C0423 - ABS Hydraulic Pump Motor Relay Circuit Malfunction in Common Chevrolet and GMC Models

Quick Answer

C0423 means: C0423 indicates a problem with the ABS hydraulic pump motor relay circuit.

Fix: Check and replace faulty components Cost: $150 - $300 Time: 90-180 minutes

Can I drive with C0423? Immediate attention is recommended to ensure safe braking.

Common Questions

What does C0423 mean and how does it affect my car?

C0423 indicates a malfunction in your vehicle's ABS hydraulic pump motor relay circuit. This can lead to impaired braking performance, especially under hard braking conditions, resulting in potential safety concerns. If this code appears, it's essential to address it promptly to maintain the integrity of your braking system.

What are the most common causes of C0423 and how much does it cost to fix?

The most frequent cause of the C0423 code is a faulty ABS hydraulic pump motor relay, costing around $150 - $300 to replace. Other causes include damaged wiring or a malfunctioning ABS control module, which can raise repair costs to $400 - $800 depending on the specific issue.

Can I drive my car with C0423 or should I stop immediately?

Driving with a C0423 code is not advisable as it indicates potential issues with your braking system. You may experience reduced braking performance, which can lead to unsafe driving conditions. It’s best to have your vehicle inspected and repaired as soon as possible.

How can I diagnose C0423 myself using GeekOBD APP?

To diagnose C0423 using the GeekOBD APP, start by connecting the app to your vehicle's OBD2 port. Perform a full scan to retrieve codes and freeze frame data. Focus on the C0423 code and any related codes, and follow the suggested diagnostic steps to check the ABS components.

What vehicles are most commonly affected by C0423?

C0423 is frequently seen in various Chevrolet and GMC models, especially those manufactured between 2000 and 2015, including the Chevrolet Silverado, GMC Sierra, and Chevrolet Equinox. It’s important to check for any recalls or technical service bulletins related to these models.

How can I prevent C0423 from happening again?

To prevent the C0423 code from recurring, conduct regular maintenance on your ABS system, including checking wiring and connections for damage or corrosion. Additionally, consider using quality replacement parts and stay informed on any recalls or updates from your vehicle's manufacturer.

What is C0423?

The diagnostic trouble code (DTC) C0423 indicates a malfunction within the Anti-lock Braking System (ABS) hydraulic pump motor relay circuit. This code is commonly associated with various Chevrolet and GMC vehicles, particularly models manufactured between 2000 and 2015, such as the Chevrolet Silverado, GMC Sierra, and Chevrolet Equinox. When the ABS system detects an abnormality in the relay circuit responsible for powering the hydraulic pump, it triggers the C0423 code. This can lead to the ABS warning light illuminating on the dashboard, which informs the driver of potential issues with the vehicle’s braking performance. The ABS system is crucial for preventing wheel lockup during hard braking, and if this code appears, it may compromise the effectiveness of the anti-lock brakes, especially in slippery conditions. Car owners may experience a drop in braking performance or an increase in stopping distances, which poses a safety risk. It’s imperative to address this code promptly by seeking professional diagnostics and repair to ensure the vehicle's braking system functions correctly.

System: C - Chassis (ABS, Steering, Suspension)

Symptoms

Common symptoms when C0423 is present:

  • ABS warning light illuminated on the dashboard, signaling potential ABS system issues.
  • Unresponsive brakes or inconsistent braking performance, causing concern during emergency stops.
  • Increased stopping distance under hard braking, which could lead to safety risks.
  • Occasional grinding or unusual noises when engaging the ABS system.
  • Intermittent brake pedal feel, ranging from spongy to overly firm during braking.

Possible Causes

Most common causes of C0423 (ordered by frequency):

  1. The most common cause of C0423 is a faulty ABS hydraulic pump motor relay, which occurs in about 60% of cases. This relay can fail due to wear over time or exposure to moisture.
  2. A second cause may involve damaged wiring in the ABS system, which could lead to poor connections and circuit failures. This can happen due to corrosion or physical damage from road debris.
  3. Another possible cause is a malfunctioning ABS control module, which can send incorrect signals to the pump motor relay. Regular checks can help prevent this by ensuring the module is functioning correctly.
  4. Less common but serious is a complete failure of the ABS hydraulic pump itself, which can be costly to replace and should be diagnosed quickly to avoid further complications.
  5. A rare cause might be software issues within the vehicle's onboard computer, which can sometimes trigger false codes and require a software update or reset.

C0423 Repair Costs

Cost Breakdown by Repair Type

ABS Hydraulic Pump Motor Relay Replacement

Replacing the faulty relay with a new OEM part to restore proper function to the ABS system.

  • Total: $150 - $300
  • Success rate: 85%
ABS Control Module Replacement

In cases where the control module is at fault, this service includes replacing the module and reprogramming it.

  • Total: $400 - $800
  • Success rate: 90%
Money-Saving Tips for C0423
  • Start with the most common and least expensive repairs first
  • Use GeekOBD APP to confirm diagnosis before replacing expensive parts
  • Consider preventive maintenance to avoid future occurrences
  • Compare prices for OEM vs aftermarket parts based on your needs
  • Address the issue promptly to prevent more expensive secondary damage

Diagnostic Steps

Professional C0423 Diagnosis Process

Follow these systematic steps to accurately diagnose C0423. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Begin with an initial visual inspection of the ABS wiring and connectors for any visible damage, loose connections, or corrosion (5-10 minutes)

Step 1: Begin with an initial visual inspection of the ABS wiring and connectors for any visible damage, loose connections, or corrosion (5-10 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 2: Step 2: Use the GeekOBD APP to perform an OBD2 scan and retrieve the C0423 code along with any related codes to understand the context of the fault (10-15 minutes)

Step 2: Use the GeekOBD APP to perform an OBD2 scan and retrieve the C0423 code along with any related codes to understand the context of the fault (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 3: Step 3: Conduct component testing using a multimeter to check the resistance and functionality of the ABS hydraulic pump motor relay (20-30 minutes)

Step 3: Conduct component testing using a multimeter to check the resistance and functionality of the ABS hydraulic pump motor relay (20-30 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 4: Step 4: Perform a system function test after any repairs to verify the ABS system operates correctly and clear the codes (10-15 minutes)

Step 4: Perform a system function test after any repairs to verify the ABS system operates correctly and clear the codes (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 5: Step 5: Complete a road test to assess the vehicle under various conditions and confirm successful repair (15-20 minutes)

Step 5: Complete a road test to assess the vehicle under various conditions and confirm successful repair (15-20 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.

Important Notes

  • Always verify the repair with GeekOBD APP after completing diagnostic steps
  • Clear codes and test drive to ensure the problem is resolved
  • Address underlying causes to prevent code recurrence

Real Repair Case Studies

Case Study 1: Failed ABS Relay Replacement in 2013 Chevrolet Silverado

Vehicle: 2013 Chevrolet Silverado 1500, 85,000 miles

Problem: Customer reported the ABS warning light was illuminated, along with intermittent brake performance.

Diagnosis: Upon scanning the vehicle, C0423 was retrieved. Visual inspection revealed a corroded ABS relay.

Solution: Replaced the ABS hydraulic pump motor relay and cleaned the connections.

Cost: $180 (including parts and labor)

Result: The ABS light turned off, and the vehicle passed a road test with normal braking performance.

Case Study 2: ABS Control Module Failure in 2010 GMC Sierra

Vehicle: 2010 GMC Sierra 2500HD, 120,000 miles

Problem: Customer experienced reduced braking effectiveness and a persistent ABS light.

Diagnosis: The GeekOBD APP revealed C0423 along with other codes indicating module failure.

Solution: Replaced the ABS control module and reprogrammed it.

Cost: $650 (specific cost breakdown included programming fees)

Result: Post-repair, the ABS system functioned correctly, and the customer reported improved braking performance.

Diagnose C0423

Use GeekOBD APP for professional diagnosis!

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  • Step-by-step repair guidance
  • Professional-grade analysis
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Code Information

Code: C0423
System: Chassis (ABS, Steering, Suspension)
Severity: HIGH
Category: Chassis Codes