B1773 — Mirror Driver Up Circuit Failure

How do I diagnose B1773 myself?

Start with a scan: confirm B1773, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the mirror driver up circuit, and verify the suspect component against live data before buying parts.

Will B1773 clear itself?

Sometimes B1773 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.

What does OBD2 code B1773 mean?

B1773 — Mirror Driver Up Circuit Failure. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: blown fuse or failed relay, corroded or loose connectors, damaged wiring in door jambs or wet areas.

How much does it cost to fix B1773?

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

Is it safe to drive with B1773?

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.

Your power mirror has stopped responding to commands to move upward, and the scan tool shows B1773. This trouble code belongs to the body control module's diagnostic family, specifically flagging a problem in the driver mirror's upward movement circuit. When you hit that switch, the module expects to see the motor respond with a specific voltage pattern. If that pattern never shows up across multiple ignition cycles, the module logs B1773 and illuminates the check-engine light.

The body control module does not set this code after a single failed attempt. It runs the circuit test repeatedly under defined conditions—typically when you operate the mirror switch—and only confirms a genuine fault after consistent failures. This is why you might notice the problem intermittently before the light appears. The stored freeze frame data captures engine load, RPM, coolant temperature, and vehicle speed at the exact moment the module detected the failure, giving you a starting point for recreation during diagnosis.

Symptoms of B1773

• The malfunction indicator lamp (MIL) glows on the instrument cluster
• The driver-side power mirror fails to move upward or moves sluggishly
• Other mirror functions—left, right, down—may still operate normally
• No effect on engine performance, transmission operation, or fuel economy
• Affected function may work sporadically before failing completely
• In some vehicles, related mirror or window circuits share wiring and may exhibit odd behavior

Common Causes

• The mirror switch itself has failed internally
• The mirror motor or actuator assembly is defective
• A fuse related to the power mirror circuit has blown
• Wiring insulation has worn through at high-flex areas like door hinges
• Connectors have corroded from moisture intrusion
• Loose pins inside the mirror harness connector cause intermittent contact
• Less commonly, the body control module itself has developed an internal fault

How to Diagnose B1773

1. Hook up your OBD2 scanner and confirm B1773 is present in the body module. Record the freeze frame data—you need those engine conditions (load, rpm, temperature, speed) to reproduce the fault state during testing.

2. Check for any accompanying diagnostic codes. Sometimes a wiring short or module power issue will generate multiple body codes pointing to the actual root cause.

3. Visually trace the mirror wiring harness. Start at the mirror assembly itself and follow the harness toward the door hinge—this is the most common failure point because wires flex every time you open and close the door.

4. Operate the mirror switch while monitoring voltage at the motor connector using a multimeter or oscilloscope. The module should be sending power and ground pulses. No voltage indicates an open circuit; constant voltage without cycling means the motor is not responding.

5. Inspect connectors for corrosion, bent pins, or loose tension. Disconnect and reconnect each connector while observing the multimeter—intermittent readings often reveal themselves this way.

6. Clear the code, then drive the vehicle through the exact conditions captured in the freeze frame. If B1773 returns, you have confirmed a hard failure rather than a one-time electrical glitch.

Repair Options and Costs

The repair approach depends entirely on what your diagnosis uncovers:

• Mirror switch replacement: $120–$450 (parts range from $40–$150 depending on make; labor adds 1–2 hours)
• Wiring harness repair or connector replacement: $80–$250 (often involves splice connectors and heat-shrink; door panel removal may be required)
• Mirror motor/actuator replacement: $150–$400 (assembly cost dominates here; some integrated mirror assemblies require full replacement)
• Body control module repair or replacement: $300–$900 (module programming may be necessary; dealer-only on many models)

Total cost for fixing B1773 typically falls between $80 and $900, depending on which component is at fault. Most failures turn out to be the switch or the wiring at the door hinge—both relatively affordable fixes. BCM replacement is the least common scenario but commands the highest price. Always verify the actual failure point before purchasing expensive control modules.

Driving Safety Verdict

Severity: Short — You can continue driving with B1773 stored. Body electrical codes do not typically affect engine operation, braking, or steering. However, a non-functional driver mirror reduces rearward visibility and should be repaired before extended highway driving or in poor weather conditions. If the mirror failure is accompanied by issues with central locking or exterior lighting, address those promptly as they affect vehicle security and safety.