B1773 — Mirror Driver Up Circuit Failure #

The description of this DTC (Diagnostic Trouble Code) may vary depending on the vehicle manufacturer. Always refer to your OEM (Original Equipment Manufacturer) service documentation for the most accurate information.

• Mirror Driver Up Circuit Short (Toyota)
• Mirror Drive Motor Up Control Circuit Malfunction (Lexus)
• Power Mirror Up Circuit Failure (Ford)

Quick Summary of Code B1773 #

B1773 signals a malfunction in the driver’s side power mirror “up” movement circuit. This means the system has detected an electrical problem—such as an open, short, or high resistance—when commanding the mirror to tilt upward. The code is most often seen in vehicles equipped with electrically adjustable mirrors, where the comfort and safety of precise mirror adjustment are essential. While this issue is not safety-critical, it can reduce convenience and may mask deeper electrical faults if left unchecked. The code can be triggered by wiring, switch, motor, or control module issues, and may be intermittent or constant.

Common Symptoms for DTC B1773 #

When B1773 is present, drivers usually notice one or more of the following symptoms. The most obvious is the inability to move the driver’s side mirror upwards using the mirror control switch. Sometimes, the entire mirror adjustment may feel sluggish, or you may hear odd noises from the mirror housing. In rare cases, other mirror directions might also act up due to shared circuits or switches.

• Driver’s side mirror does not tilt upward
• Mirror adjustment makes clicking or grinding noises
• Mirror only moves in some directions (left, right, down, but not up)
• Erratic or intermittent mirror movement
• Other power mirror positions may also malfunction

Likely Causes for Code B1773 #

The most frequent causes of B1773 relate to the mirror’s electrical or control systems. These range from simple issues like a faulty switch to more involved problems like wiring damage or a failing mirror motor. Here’s how they rank in likelihood:

1. Defective mirror adjustment switch (most common)
2. Faulty mirror drive motor (up direction)
3. Wiring issues (broken, shorted, or corroded wires in the door harness)
4. Poor electrical connector contact (loose or oxidized pins at the switch, motor, or control module)
5. Fault in the door control module (rare, but possible if all else checks out)

Step-by-Step Diagnosis for B1773 #

Proper diagnosis is key to avoiding unnecessary parts replacements. Follow these steps methodically to pinpoint the root cause of B1773:

• Confirm the code with an OEM-compatible scan tool and clear it to see if it returns.
• Test the mirror operation in all directions. Note specifically if only the “up” function fails.
• Inspect the mirror adjustment switch for physical damage or stickiness; test output with a multimeter if possible.
• Check wiring continuity between the switch and mirror motor using a wiring diagram. Look for obvious pinches or breaks, especially in the door harness where wires flex.
• Inspect electrical connectors for corrosion, loose pins, or water intrusion.
• Test the mirror drive motor directly by applying 12V to the up circuit; if it doesn’t move, the motor is likely faulty.
• If all hardware checks out, consider the door module. Test for proper command signals and replace only if necessary.

Possible Repairs for B1773 #

The right repair depends on your diagnostic results. Start with the most probable causes before proceeding to more complex ones. Here’s how you might resolve B1773:

• Replace the mirror adjustment switch if it fails continuity or output tests.
• Repair or replace damaged wiring in the mirror up circuit, particularly at flex points in the door.
• Clean, tighten, or replace corroded connectors at the switch, motor, or module.
• Install a new mirror drive motor if the up direction fails on direct power.
• Replace the door module only if all else passes and module testing confirms failure.

Is It Safe to Drive with Code B1773? #

Yes, you can continue driving with code B1773 present, but with limited convenience. The primary risk is loss of upward adjustment on the driver’s mirror, which can reduce optimal visibility and comfort. However, the fault does not affect essential safety or drivability functions. Prompt repair is recommended to restore full mirror adjustment and avoid future electrical issues.

Vehicles Most Commonly Affected by B1773 #

This DTC tends to appear most frequently on models with power mirrors from the late 1990s to present day. Japanese manufacturers like Toyota and Lexus are often associated, but any OEM using similar mirror systems can be affected. The following vehicles are among those most commonly reporting B1773:

• Toyota Camry (various years)
• Lexus ES and RX series
• Ford F-150 (certain trims with power mirrors)
• Honda Accord (with memory mirrors)
• Nissan Altima (recent generations)

Common Mistakes & Best Practices with B1773 #

Many DIYers and even some technicians make avoidable errors when addressing B1773. Here are the most frequent pitfalls and how to avoid them:

• Replacing the mirror motor without first testing the switch or wiring
• Overlooking broken or pinched wires in the door hinge area
• Ignoring intermittent faults—always wiggle test the harness during diagnosis
• Failing to clear codes and confirm repair before reassembly
• Not consulting the OEM wiring diagram, leading to misdiagnosis

Express FAQ for Code B1773 #

Here are quick answers to the most common questions regarding B1773:

Q: Will B1773 trigger a warning light on my dashboard?
A: Usually, no. Most vehicles do not illuminate the main warning lights for mirror circuit faults, though you may see a message in the vehicle status menu.

Q: Can I manually adjust my mirror if B1773 is set?
A: If your mirror has a manual override, you can adjust it by hand. However, forcing movement on a stuck power mirror may cause further mechanical damage—exercise caution.

If you suspect a B1773 fault, a patient and logical approach will save you time and money. Addressing the root cause not only restores comfort but ensures your vehicle’s electrical systems remain reliable for the road ahead.