What Does P1791 Mean?
The transmission range display circuit has a short to ground, preventing proper communication of gear position to the instrument cluster. This typically means a wire in the harness between the transmission range sensor and the display has contacted a ground source.
Common Causes
45%
Damaged or chafed wiring harness between transmission and instrument cluster
30%
Corroded or damaged connector pins at transmission range sensor or cluster
15%
Failed transmission range sensor with internal short
10%
Faulty instrument cluster circuit board
Diagnostic Steps
1
Step 1: Visually inspect wiring harness from transmission range sensor to instrument cluster for damage, chafing, or pinch points
2
Step 2: Disconnect transmission range sensor connector and measure resistance between display circuit wire and ground (should be infinite/open)
3
Step 3: Check connector pins for corrosion, bent pins, or moisture intrusion at both transmission and cluster ends
4
Step 4: Backprobe the circuit with a test light while wiggling harness to identify intermittent short locations
5
Step 5: If wiring tests good, substitute test transmission range sensor or instrument cluster to isolate failed component
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
The transmission range display circuit has a short to ground, preventing proper communication of gear position to the instrument cluster. This typically means a wire in the harness between the transmission range sensor and the display has contacted a ground source.
The most common cause of P1791 (Transmission Range Display Circ. Short to Ground) is: Damaged or chafed wiring harness between transmission and instrument cluster
Typical repair costs for P1791 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Incorrect gear position display may confuse driver about actual transmission state. Vehicle may not start if PCM cannot verify park/neutral position.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1791 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission Control and Display
Difficulty
Type
Manufacturer
Recommended Tools
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