B1658 — Seat Driver Rear Up Circuit Short To Ground

OBD2 code B1658 flags a problem with the body electrical system (seat driver rear up circuit short to ground). The car is usually drivable while you plan the repair. Common culprits: blown fuse or failed relay, faulty switch, motor or actuator of the affected system, corroded or loose connectors.

body electrical

Is it safe to drive?

Short-term driving is OK Usually safe to drive — body codes rarely affect drivability. Exceptions: exterior lighting and wipers in bad weather, and central locking faults that can leave the car unsecured.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm B1658 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many B0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the body electrical system for damage, corrosion, chafing or poor contact.
Subsystem check Operate the affected function while watching its switch and motor PIDs in live data.
Subsystem check Inspect connectors and wiring at flex points (door jambs, tailgate hinges) — wires break there first.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm B1658 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B1658 (parts and labor, USD, independent shop rates): BCM repair or replacement: $300–$900; Repair wiring or connectors: $80–$250; Replace the switch or actuator: $120–$450. Overall, fixing B1658 usually costs between $80 and $900. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What does OBD2 code B1658 mean?

Will B1658 clear itself?

Sometimes B1658 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

How much does it cost to fix B1658?

BCM repair or replacement — $300–$900; Repair wiring or connectors — $80–$250; Replace the switch or actuator — $120–$450. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

What are the symptoms of B1658?

Drivers most often notice: no impact on engine operation in most cases, warning light on the dashboard, the affected function (locks, windows, lighting, wipers) works intermittently or not at all.

How do I diagnose B1658 myself?

Start with a scan: confirm B1658, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the body electrical system, and verify the suspect component against live data before buying parts.

When your scan tool displays B1658, the vehicle's body control module has identified an electrical problem within the driver seat's rear-up adjustment circuit. This code belongs to the B-series family, which covers body control systems like power windows, door locks, seat motors, lighting, and windshield wipers. B1658 specifically tells you that the circuit responsible for raising the rear portion of the driver's seat has a direct short to ground — meaning electrical current is flowing where it shouldn't and bypassing the normal circuit path entirely.

Modern vehicles rely on a body control module to monitor every electrical function in the passenger compartment. Each circuit has expected voltage and resistance ranges. When the module sees values that fall outside those parameters — in this case, the telltale signature of a ground short — it logs B1658. The code typically sets after the fault is confirmed across multiple drive cycles rather than triggering on a single momentary glitch. The module also captures a freeze frame when the code is set, recording engine RPM, calculated load, coolant temperature, and vehicle speed at that exact moment. Reviewing this snapshot first narrows down whether the fault occurs only at idle, under acceleration, or during specific weather conditions.

The good news is that B1658 doesn't touch your engine management system. Body codes operate on a completely separate network from the powertrain control module, so your engine will run, accelerate, and shift normally. You may notice the driver seat's rear-up adjustment no longer responds to the switch, or the seat moves sluggishly and erratically when it does work. A dashboard warning light — sometimes a generic "check engine" light that turns out to be body-related — will likely accompany the code.

Common Symptoms of B1658

The driver's seat fails to adjust rearward or upward, or adjusts only intermittently
Seat movement is accompanied by grinding, clicking, or humming noises from the motor
The seat adjustment switch feels unresponsive or stuck in one position
A warning indicator appears on the instrument cluster
Engine performance, fuel economy, and transmission function remain completely normal
Other seat adjustment functions — forward/back, recline, lumbar — operate normally if they use separate circuits
The fault may come and go, particularly in wet weather or after the vehicle sits overnight

What Causes B1658?

Damaged wiring at flex points — the seat wiring harness flexes every time you adjust the seat, and the rear-up circuit wires break first at those stress points
Moisture intrusion in connectors — spilled drinks, rain water, or car washes introduce corrosion that creates false ground paths
Failed seat motor — the motor's internal commutator or brushes can short internally, pulling current directly to ground
Worn adjustment switch — switch contacts pit and oxidize over time, eventually creating resistance that the module interprets as a fault
Harness damage during service — improper seat removal or reinstallation can pinch or chafe wires without obvious exterior damage
Body control module failure — though less common, the BCM itself can develop internal shorts in its output drivers

How to Diagnose B1658

Retrieve all codes and freeze frame data — connect your OBD2 scanner, record every stored code including pending codes, and save the freeze frame attached to B1658. The freeze frame conditions often point directly to the failure scenario.
Check for related codes and technical service bulletins — codes like B1656 or B1657 in the same family suggest a broader harness issue. Search the NHTSA database and your manufacturer's site for TSBs covering B1658 on your specific model year.
Inspect the seat harness visually — remove the seat or access the harness per your service manual. Focus on the areas where wires bend: the seat track junction, the connector to the motor, and the switch wiring under the seat cushion.
Test for short-to-ground with a multimeter — disconnect the motor and switch connectors, then check resistance between the circuit wire and chassis ground. A reading under 1 ohm confirms a direct short somewhere in the harness.
Operate the switch while monitoring live data — with the scanner in data stream mode, actuate the rear-up switch and watch the circuit's voltage and current draw. A failing motor will show abnormal amp draw or voltage drop.
Clear the code and road-test — erase B1658, complete a drive cycle that reproduces the freeze frame conditions (same speed, load, and temperature), and verify the code does not return.

Repair Options and Costs

The fix depends entirely on which component the diagnosis points to. Work through cheaper possibilities before replacing expensive modules:

Wiring repair — if the harness is chafed or broken, splice and seal the damaged section. Many shops charge $80–$250 for this work depending on access