Gear Shift Module Communication Circuit High
The P0862 code means the vehicle's onboard diagnostic system has detected: Gear Shift Module Communication Circuit High. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $200 - $1,000 (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.
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Common Symptoms
- Check Engine Light illuminated
- Loss of shift module communication
- Vehicle stuck in Park or current gear
- Multiple warning lights on dashboard
Probable Causes (Ranked by Likelihood)
- CAN bus high wire open or shorted to battery voltage Very High
- Gear shift module internal fault pulling bus high High
- Missing CAN bus termination resistor Moderate
- TCM CAN bus transceiver failure Low
Step-by-Step Diagnostic Procedure
-
Measure CAN bus high and low voltages at the shift module connector
-
Check for open CAN bus wires or damaged connectors
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Verify CAN bus termination resistance (should be approximately 60 ohms)
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Disconnect shift module to see if communication restores on other modules
Frequently Asked Questions
Is P0862 the opposite of P0861?
Yes. P0861 indicates the CAN bus signal is stuck low and P0862 indicates it is stuck high. Both prevent communication with the gear shift module.
Can CAN bus issues affect multiple systems simultaneously?
Yes, the CAN bus is a shared communication network. A fault on one node can disrupt all modules on the same bus, causing widespread DTCs.
What is a CAN bus termination resistor?
CAN bus networks require a 120-ohm termination resistor at each end of the bus to prevent signal reflections. If one is missing or damaged, communication errors can occur.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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