C1805 Code - Mismatched PCM and/or ABS Module
Quick Answer
When the ignition is turned to the RUN position, the Anti-Lock Brake System (ABS) Module and the Powertrain Control Module (PCM) share Vehicle Identification Number (VIN) information over the High Speed Controller Area Network (HS-CAN) bus. Common causes include Reprogram Powertrain Control Module (PCM) ("Flashing"), Faulty Anti-Lock Brake System (ABS) Module, Anti-Lock Brake System (ABS) Module harness is open or shorted. 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
- C1805 indicates Mismatched PCM and/or ABS Module.
- Common causes
- Common causes include Reprogram Powertrain Control Module (PCM) ("Flashing"), Faulty Anti-Lock Brake System (ABS) Module, Anti-Lock Brake System (ABS) Module harness is open or shorted.
- 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.
Code C1805 Description
What are the Possible Causes of the DTC C1805?
- Reprogram Powertrain Control Module (PCM) ("Flashing")
- Faulty Anti-Lock Brake System (ABS) Module
- Anti-Lock Brake System (ABS) Module harness is open or shorted
- Anti-Lock Brake System (ABS) Module circuit poor electrical connection
- Faulty Powertrain Control Module (PCM)
How to Fix the DTC C1805?
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 C1805 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
- C1805 Ford — Mismatched PCM and/or ABS Module
- C1805 Infiniti — Air Suspension Vehicle Height Adjustment Down
- C1805 Lincoln — Mismatched PCM and/or ABS Module
- C1805 Mercury — Mismatched PCM and/or ABS Module
- C1805 Nissan — Air Suspension Vehicle Height Adjustment Down
Frequently Asked Questions about C1805 Code
1. What are the common symptoms of OBDII code C1805 (Mismatched PCM and/or ABS Module)?
The common symptoms include the ABS light and/or the traction control light illuminating on the dashboard, possible loss of ABS functionality, and potential issues with the vehicle's stability control system.
2. What can cause the OBDII code C1805 to occur?
This code typically occurs when there is a communication error between the Powertrain Control Module (PCM) and the Anti-lock Braking System (ABS) module, often due to a mismatch in software or hardware configurations.
3. How can I diagnose the cause of OBDII code C1805?
Diagnosing the cause of this code usually involves using a professional OBDII scanner to retrieve the specific fault codes, checking the connections between the PCM and ABS module, and verifying the software versions of both modules.
4. Can a software update fix the OBDII code C1805 issue?
In some cases, updating the software of either the PCM or ABS module can resolve the mismatched configuration causing the code C1805. It is recommended to consult a professional technician for software updates.
5. Is it safe to continue driving with OBDII code C1805 present?
While the vehicle may still be operational with this code, it is not recommended to drive for an extended period without addressing the issue. Loss of ABS functionality can compromise vehicle safety during braking and stability control.
6. How much does it typically cost to repair OBDII code C1805?
The cost of repairing this code can vary depending on the root cause of the issue. Repairs may involve software updates, module reprogramming, or even module replacements, ranging from a few hundred to over a thousand dollars.
7. Can I reset the OBDII code C1805 with a simple reset tool?
Resetting the code with a basic OBDII code reader may temporarily clear the fault code, but if the underlying issue causing the mismatched PCM and ABS module is not addressed, the code is likely to reappear.
8. Will disconnecting the battery reset OBDII code C1805?
Disconnecting the battery may reset the fault codes temporarily, but it will not fix the underlying issue causing the mismatch between the PCM and ABS module. It is advisable to diagnose and repair the problem properly.
9. Are there any DIY repair tips for OBDII code C1805?
DIY repair for this code is limited, as it often requires professional diagnostic equipment and expertise. However, checking and cleaning the connections between the PCM and ABS module may sometimes resolve communication issues.
10. How long does it take to repair OBDII code C1805?
The repair time for this code can vary depending on the complexity of the issue and the availability of parts or software updates. Simple fixes like software updates may take less than an hour, while more involved repairs could take several hours or more.
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