P0837: Four Wheel Drive (4WD) Switch Circuit Range/Performance
What to do
The selection may not match what the vehicle actually does. If four-wheel drive is rarely used, mention that — actuators seize from standing unused, and it is a common cause on a vehicle that has spent years in two-wheel drive.
What this code means
The four-wheel-drive switch signal is present but implausible — most often a selection that does not match what the transfer case reports having done, or two selections indicated at once.
Disagreement between the switch and the transfer case is the informative case, because it separates a request from a result. The driver asked for four-wheel drive, the switch reported it, and the transfer case did not get there — which points at the actuator or at the mechanism rather than at the switch the code names. Transfer case actuators seize from disuse on vehicles that spend their lives on tarmac, which is why exercising the system occasionally is worth doing.
Likely causes
Start here
- Faulty transfer case actuator · specialist
- Faulty four wheel drive switch · easy
Less common
- Seized transfer case shift mechanism · specialist
- Road damage to underfloor wiring · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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