What Does P0862 Mean?
The gear shift module communication circuit is reading a high voltage condition. The communication line voltage exceeds the maximum acceptable threshold, indicating a short to battery voltage, an open ground circuit, or a module malfunction driving the line high. The TCM/PCM cannot receive valid gear selection data under this condition.
Common Causes
30%
Short to battery voltage in the communication wiring
25%
Open ground circuit at the gear shift module
25%
Faulty gear shift module with high output state
12%
Disconnected connector causing an open circuit
8%
TCM communication line driver failure
Diagnostic Steps
1
Measure the communication circuit voltage at the gear shift module connector to confirm the high-voltage reading.
2
Disconnect the gear shift module and recheck — if the voltage drops to zero, the module is producing the high signal. If it stays high, the wiring has a short to power.
3
Check the ground circuit for the gear shift module — measure continuity from the module ground pin to chassis ground.
4
Trace the communication wiring and inspect for insulation damage where it may contact power wires or connectors.
5
If the ground and wiring are intact, replace the gear shift module and verify the communication circuit voltage returns to normal.
Estimated Repair Cost
$200 - $900
Parts + labor, varies by vehicle and location
The gear shift module communication circuit is reading a high voltage condition. The communication line voltage exceeds the maximum acceptable threshold, indicating a short to battery voltage, an open ground circuit, or a module malfunction driving the line high. The TCM/PCM cannot receive valid gea...
The most common cause of P0862 (Gear Shift Module Communication Circuit High) is: Short to battery voltage in the communication wiring
Typical repair costs for P0862 range from $200 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Gear selection commands from the shifter may not reach the TCM, making the vehicle unable to change gears. If the shifter is non-functional, the vehicle should not be driven and should be towed to a repair shop.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0862 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission / Electronic Shift Control
Difficulty
Type
Generic (SAE)
Recommended Tools
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