← Back to Search Severity: Medium

P0859

P0859: Transmission Control Module (TCM) Range/Performance Issue

Fix Cost
$200 - $800
Parts & Labor
Difficulty
3/5
Moderate
1-2 hours
DIY Possible?
❌ No
Pro recommended
Category
Powertrain
System

📖 What Does P0859 Mean?

The Transmission Control Module (TCM) has detected a range or performance issue with the transmission's gear shifting or torque converter engagement.
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Symptoms

  • Transmission slips
  • hesitates
  • or refuses to engage gears
  • unusual noises
  • or the 'check engine' light comes on.
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Common Causes

  • Faulty transmission solenoid
  • clogged transmission filter
  • low transmission fluid level
  • faulty TCM
  • or wiring issues.
Fix Guide
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Possible Solutions

1. Check transmission fluid level and condition. 2. Inspect and clean the transmission filter. 3. Test the transmission solenoids. 4. Update the TCM software. 5. Replace the faulty solenoid or TCM if necessary.

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Common Questions About P0859

Q

Can I drive with code P0859?

A

You can drive for a short time, but should address code P0859 soon to avoid worsening the problem or failing an emissions test.

Q

How much does it cost to fix P0859?

A

The estimated repair cost for code P0859 is between $200 and $800. This includes parts and labor for most makes and models.

Q

Is this code easy to fix myself?

A

This repair is considered moderate. It may require specialized tools or significant disassembly. Professional help is recommended if you aren't an experienced DIYer.

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Need a Pro?

Complex codes like P0859 can be tricky. Don't risk it if you're unsure.

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Related Diagnostic Codes

Other codes that may appear with P0859

💡 Why These Codes Are Related:

  • Similar Issues: Same root cause or component failure
  • Related Problems: Often occur together due to system interactions
  • Sequential Codes: Progressive failure stages or multiple sensors
  • Same System: Components within the same automotive system