What Does P2791 Mean?
The PCM has detected that the gate select direction circuit voltage is below the expected threshold. This indicates a short to ground or circuit fault preventing proper gear selector position signal transmission to the control module.
Common Causes
35%
Gate select sensor circuit shorted to ground
30%
Faulty gate select position sensor shorted internally
20%
Damaged or pinched wiring harness
10%
Corroded connector causing internal short
5%
TCM/PCM internal circuit failure
Diagnostic Steps
1
Step 1: Disconnect gate select sensor connector and measure reference voltage at harness side - should read system reference voltage
2
Step 2: Check for short to ground on signal wire with sensor disconnected using ohmmeter
3
Step 3: Inspect wiring harness routing for pinched, chafed, or damaged areas near shifter mechanism
4
Step 4: Test gate select sensor resistance values in all shift positions; compare to specifications
5
Step 5: If circuits and sensor test normal, verify TCM/PCM ground circuits and suspect module fault
Estimated Repair Cost
$120 - $550
Parts + labor, varies by vehicle and location
The PCM has detected that the gate select direction circuit voltage is below the expected threshold. This indicates a short to ground or circuit fault preventing proper gear selector position signal transmission to the control module.
The most common cause of P2791 (Gate Select Direction Circuit Low) is: Gate select sensor circuit shorted to ground
Typical repair costs for P2791 range from $120 to $550, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may not recognize gear selection, potentially preventing starting or causing unexpected transmission behavior. May result in being stuck in one gear or limp mode.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2791 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission Shift Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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