B1741
Mirror Passenger Vertical Switch Circuit Failure
Body Chassis/Safety Mirror Control System 🟢 Low — Fix at next service
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What This Actually Means
In plain language — no jargon

The passenger side mirror's vertical (up/down) control switch is sending an electrical signal that the car can't read properly, similar to a broken volume button on a remote control. The ECU detects this circuit malfunction and stores the fault code.

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Symptoms You May Notice
3 known symptoms for this code
Passenger mirror vertical adjustment not responding to switch input
Mirror stuck in one position or moves erratically
Dashboard warning light or fault code displayed
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors voltage signals from the passenger mirror vertical switch circuit as the driver operates the control. It expects clean digital or analog signals within specific voltage ranges when the switch is pressed. If the circuit shows open, short, or out-of-range voltage conditions, the fault is logged.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Switch circuit voltage 0-5V with clear state transitions Open circuit (12V+) or short to ground (<0.2V) when switch activated
Circuit resistance Varies by switch position (typically 100-1000 ohms) Infinite resistance (open) or <10 ohms (short)
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Mirror control switch connector
Inspect and reseat the passenger mirror switch connector under the door panel for loose or corroded pins.
2
Mirror switch assembly
Replace the faulty vertical switch unit if contacts are worn or damaged after checking wiring continuity.
3
Mirror wiring harness
Replace damaged or pinched wiring between the door panel and mirror motor if continuity test fails.