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P1853

Transmission Transfer Case Contact Plate 'B' Short Circuit To Ground.

  • Other
  • Powertrain
  • Manufacturer code
  • Medium severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
8
AreaTransmission
53
FaultThe specific fault in that area

What it means

P1853 on this make is read as a short to ground on the 'B' circuit of the transfer case contact plate, the position or range contact assembly that tells the control unit which 4WD or range mode is selected. The control unit saw that circuit pulled to ground when it should have shown a valid switch state. Exact circuit layout and wire colours vary by model, so check the manufacturer wiring information for the vehicle.

Symptoms

  • Transmission or 4WD warning light on the dash
  • 4WD or range indicator flashing, wrong or not responding
  • Transfer case will not change between 2WD, 4WD high or low range
  • Harsh or restricted gearshifts, or transmission held in a limp mode
  • Stored fault with no obvious change in how the car drives

Possible causes

  • Wiring to the transfer case contact plate chafed or pinched, shorting to groundlikely
  • Contact plate or position switch internally faulty or wornlikely
  • Water, dirt or corrosion in the connector at the transfer case giving a path to groundpossible
  • Transfer case shift motor or selector linkage out of position, giving a false readingpossible
  • Damaged wiring harness near the exhaust, driveshaft or underbody mountingspossible
  • Fault inside the transmission or transfer case control unitrare

How to diagnose

  1. Read all stored and pending codes and freeze frame data, then note whether the fault is current or intermittent
  2. Check the transfer case selector position shown on a scan tool against the actual selected mode
  3. Inspect the wiring and connector at the transfer case for chafing, heat damage, water, corrosion or pushed-back pins
  4. Check the harness along its route for rubbing points or signs of contact with the underbody or driveline
  5. With the connector unplugged and ignition off, test the 'B' circuit for continuity to ground using the manufacturer wiring diagram
  6. Compare the contact plate resistance or switch states through each selector position with the specification for the model
  7. Check the shift motor and linkage move freely and reach each position fully
  8. If wiring and the contact plate test good, check the control unit supply, grounds and for any software updates relevant to the fault

How to fix

  • Repair or replace the damaged wiring section, using proper soldered and sealed joins
  • Clean, dry and re-seat the connector, replacing it if terminals are corroded or damaged
  • Replace the transfer case contact plate or position switch if it tests faulty
  • Repair or adjust the shift motor and linkage if they cause a false position reading
  • Re-route and secure the harness clear of heat and moving parts
  • Repair or replace the control unit only after the wiring and switch are proven good

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but 4WD or range selection may be unreliable. Avoid off-road use and towing, and stop if the transmission is stuck in a mode or shifting badly.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

This code for other makes

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