Transfer Case Control System MIL Request
The P0800 code means the vehicle's onboard diagnostic system has detected: Transfer Case Control System MIL Request. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $150 - $1,200 (parts and labor)
Read and clear transmission codes. Many trans codes are caused by low or burnt fluid -- check level and color before assuming the worst.
Basic scanners only read engine codes. This reads transmission, ABS, and airbag too.
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Common Symptoms
- Check Engine Light illuminated
- Transfer case warning light on
- Difficulty shifting between 2WD and 4WD
- Unusual noises from the transfer case
Probable Causes (Ranked by Likelihood)
- Transfer case control module malfunction Very High
- Faulty transfer case motor or encoder High
- Wiring or connector issue in transfer case circuit Moderate
- Low or contaminated transfer case fluid Low
Frequently Asked Questions
Can I still drive my vehicle with P0800?
You can drive short distances, but the transfer case may not shift properly. Avoid off-road or slippery conditions until the issue is resolved.
Is P0800 expensive to fix?
It depends on the root cause. A wiring fix or fluid change is inexpensive, but a faulty transfer case motor or control module can cost $500 to $1,200.
Does P0800 only appear on 4WD vehicles?
Yes, P0800 is specific to vehicles with a transfer case, which includes 4WD and AWD vehicles.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
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Scan for additional transfer case DTCs to pinpoint the specific fault
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Inspect the transfer case control module connector for corrosion or damage
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Check transfer case fluid level and condition
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Test the transfer case motor and encoder ring with a scan tool
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
Commonly Affected Vehicles
- 2007-2018 Jeep Wrangler
- 2005-2019 Ford F-150 4WD
- 2007-2017 Chevrolet Silverado 4WD
- 2005-2015 Toyota Tacoma 4WD
Related Codes
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