Introduction:
The B1658 diagnostic trouble code (DTC) indicates an electrical fault within the driver's seat adjustment system of a vehicle. Specifically, it pinpoints a short-to-ground condition in the "Rear Up" circuit, which controls the upward movement of the rear portion of the driver's seat. Understanding the causes and troubleshooting steps for this code is crucial for restoring full functionality to the seat and ensuring driver comfort and safety.
Table: B1658 Seat Driver Rear Up Circuit Short To Ground Details
| Topic | Description | Possible Causes |
|---|---|---|
| Code Definition | Identifies a short circuit to ground within the driver's seat "Rear Up" adjustment circuit. This means the electrical signal is unintentionally connecting to the vehicle's chassis ground before reaching its intended destination. | Damaged wiring harness (pinched, frayed, or cut wires) Faulty seat adjustment motor Short circuit within the seat adjustment switch Corrosion in connectors Faulty seat control module (SCM) Wiring rubbing against the seat frame or other metal components * Aftermarket seat installations or modifications that damaged the wiring |
| Symptoms | Driver's seat rear portion does not move upwards Driver's seat may move downwards but not upwards in the rear Seat adjustment motor may be inoperative or slow Check Engine Light (CEL) illuminated Other seat functions may be affected (depending on the vehicle's system design) Possible blown fuse related to the seat adjustment circuit * Seat position memory not working properly (if equipped) | |
| Diagnostic Steps | 1. Visual inspection of wiring and connectors 2. Fuse check 3. Circuit testing with a multimeter (continuity and voltage checks) 4. Component testing (seat motor, switch, SCM) 5. Wiring harness repair or replacement 6. Connector cleaning and repair 7. SCM replacement (if proven faulty) 8. Check for aftermarket accessories/modifications impacting wiring. 9. Consult vehicle-specific wiring diagrams. 10. Check for Technical Service Bulletins (TSBs) related to the issue. | |
| Common Tools Required | Multimeter, wiring diagram, wire strippers, crimpers, electrical tape, connector cleaner, test light, fuse puller, OBD-II scanner (for code clearing), trim removal tools, socket set, wrench set. | N/A |
| Related Codes | B1657 (Seat Driver Rear Down Circuit Short To Ground), B1659 (Seat Driver Front Up Circuit Short To Ground), B1660 (Seat Driver Front Down Circuit Short To Ground), other seat-related codes that could indicate broader issues with the seat adjustment system. Codes related to the seat control module (SCM) itself. | N/A |
| Potential Repair Costs | Varies greatly depending on the cause. Simple wiring repair could be $50-$200. Motor replacement could be $200-$500. SCM replacement could be $300-$800 or more (including programming). Labor costs also vary widely depending on the shop rate and the complexity of the repair. Diagnostic fees can range from $80-$150. | N/A |
| Safety Precautions | Disconnect the negative battery terminal before working on electrical components. Use proper safety glasses and gloves. Be careful when working around airbags and other safety systems. Consult the vehicle's repair manual for specific safety instructions. Avoid probing connectors from the front unless specifically designed to do so, as this can damage the terminals. Ensure the vehicle is parked on a level surface and the parking brake is engaged. | N/A |
Detailed Explanations:
Code Definition: The B1658 code signifies a short circuit to ground within the circuit responsible for raising the rear portion of the driver's seat. A short to ground means that the electrical current intended for the seat motor is finding an unintended path to the vehicle's chassis (ground), bypassing the motor and causing a malfunction. This usually happens when a wire's insulation is damaged, allowing the bare wire to touch metal.
Symptoms: The most obvious symptom is the inability to raise the rear of the driver's seat. Other symptoms may include the Check Engine Light illuminating, intermittent operation of the seat, or even a blown fuse in the seat adjustment circuit. In some cases, other seat functions might be affected if they share the same power supply or control module. The seat memory function (if equipped) might also malfunction because the seat cannot reach the programmed positions.
Diagnostic Steps:
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Visual Inspection: Begin by thoroughly inspecting the wiring harness and connectors associated with the driver's seat. Look for any signs of damage, such as pinched, frayed, cut, or melted wires. Pay close attention to areas where the wiring harness passes through the seat frame or other metal components, as these are common areas for chafing. Check the connectors for corrosion or loose connections.
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Fuse Check: Consult the vehicle's owner's manual or repair manual to locate the fuse that protects the driver's seat adjustment circuit. Visually inspect the fuse to see if it is blown. If the fuse is blown, replace it with a new fuse of the correct amperage rating. If the fuse blows again immediately, this confirms a short circuit in the system.
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Circuit Testing with a Multimeter: A multimeter is essential for diagnosing electrical problems. First, disconnect the seat motor connector. Then, perform a continuity test between the "Rear Up" circuit wire and the vehicle's chassis ground. A continuity reading indicates a short to ground. Next, with the ignition on (but the seat motor still disconnected), perform a voltage test on the "Rear Up" circuit wire. You should see battery voltage when the seat adjustment switch is activated in the "Rear Up" direction. If you don't see voltage, the problem could be with the switch or the wiring leading to it.
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Component Testing: Test the seat motor by applying direct power and ground to its terminals. If the motor doesn't operate, it's likely faulty. Test the seat adjustment switch by using a multimeter to check for continuity between the appropriate terminals when the switch is activated. Test the seat control module (SCM) by checking its power and ground connections and verifying that it is sending the correct signals to the seat motor when the switch is activated. This often requires a specialized scan tool.
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Wiring Harness Repair or Replacement: If you find damaged wiring, repair it using proper wiring repair techniques. This may involve splicing wires, using heat shrink tubing, and wrapping the repaired area with electrical tape. If the wiring is severely damaged, it may be necessary to replace the entire wiring harness.
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Connector Cleaning and Repair: Clean corroded connectors with a connector cleaner. If the connector terminals are damaged, they may need to be replaced.
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SCM Replacement: If all other components test good, and the wiring is intact, the SCM may be faulty. Replacing the SCM often requires programming the new module to the vehicle's computer system.
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Aftermarket Accessories/Modifications: Check for any aftermarket accessories, such as aftermarket seat heaters or lumbar support systems, that may have been installed incorrectly and damaged the wiring. Remove or repair any faulty aftermarket installations.
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Consult Wiring Diagrams: Always consult the vehicle's wiring diagrams to understand the specific circuit layout and identify the correct wires to test.
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Technical Service Bulletins (TSBs): Search for Technical Service Bulletins (TSBs) issued by the vehicle manufacturer that may address known issues with the seat adjustment system on your specific make and model.
Common Tools Required: A multimeter is indispensable for electrical testing. Wiring diagrams are essential for understanding the circuit layout. Wire strippers, crimpers, and electrical tape are needed for wiring repairs. Connector cleaner helps remove corrosion from connectors. A test light can be used to quickly check for power and ground. A fuse puller makes it easier to remove fuses. An OBD-II scanner is needed to clear the DTC after the repair is completed. Trim removal tools help remove interior panels without damaging them. A socket set and wrench set are needed to remove and install components.
Related Codes: Other seat-related codes, such as B1657 (Seat Driver Rear Down Circuit Short To Ground), B1659 (Seat Driver Front Up Circuit Short To Ground), and B1660 (Seat Driver Front Down Circuit Short To Ground), may indicate similar issues with other seat adjustment circuits. Codes related to the seat control module itself can also point to more widespread problems within the seat system.
Potential Repair Costs: The cost of repair can vary greatly depending on the cause of the problem. A simple wiring repair may only cost $50-$200. A motor replacement could cost $200-$500. An SCM replacement could cost $300-$800 or more, including programming. Labor costs will also vary depending on the shop rate and the complexity of the repair. Diagnostic fees typically range from $80-$150.
Safety Precautions: Always disconnect the negative battery terminal before working on electrical components to prevent accidental shocks or damage to the vehicle's electrical system. Wear safety glasses and gloves to protect yourself from injury. Be especially careful when working around airbags and other safety systems. Consult the vehicle's repair manual for specific safety instructions. Avoid probing connectors from the front unless specifically designed to do so, as this can damage the terminals. Ensure the vehicle is parked on a level surface and the parking brake is engaged to prevent it from rolling.
Frequently Asked Questions:
What does the B1658 code mean? It indicates a short circuit to ground in the driver's seat rear up adjustment circuit. This means the electrical current is finding an unintended path to ground.
Can I fix this problem myself? If you have experience with electrical diagnostics and repairs, you can attempt to fix it yourself. However, if you're not comfortable working with electrical systems, it's best to take it to a qualified mechanic.
What tools do I need to diagnose this code? You'll need a multimeter, wiring diagrams, wire strippers, crimpers, electrical tape, connector cleaner, test light, fuse puller, OBD-II scanner, trim removal tools, a socket set, and a wrench set.
How much will it cost to fix the B1658 code? The cost can vary widely depending on the cause of the problem, ranging from $50 for a simple wiring repair to $800 or more for an SCM replacement.
What happens if I ignore the B1658 code? Ignoring the code can lead to further damage to the seat adjustment system. It can also be a safety concern if you cannot properly adjust your seat.
Is it safe to drive with the B1658 code? While generally safe, the inability to properly adjust the driver's seat could compromise your driving position and potentially impact safety in an accident.
Where can I find wiring diagrams for my vehicle? Wiring diagrams can be found in the vehicle's repair manual or online through subscription services like AllData or Mitchell OnDemand.
Can a bad seat motor cause this code? Yes, a short circuit within the seat motor can cause this code. It's crucial to test the motor for internal shorts.
Does this code affect other seat functions? It can, depending on the vehicle's system design. Some seat functions might share power or control circuits.
Will clearing the code make the problem go away? Clearing the code will only temporarily remove the warning light. The underlying problem must be fixed to prevent the code from returning.
Conclusion:
The B1658 code signifies a specific electrical problem in the driver's seat adjustment system. A methodical approach to diagnosis, starting with a visual inspection and progressing to circuit testing, is key to identifying and resolving the short to ground. Addressing this issue promptly will restore full seat functionality and ensure driver comfort and safety.