What Does P1543 Mean?
The throttle actuator potentiometer is reporting a signal voltage that is below the minimum acceptable threshold. This indicates either a sensor circuit issue or mechanical problem with the throttle position sensor.
Safety Warning
Vehicle will likely enter limp mode with severely restricted throttle operation. May have difficulty accelerating or maintaining speed. Not safe for highway driving.
Common Causes
35%
Open circuit or short to ground in throttle position sensor wiring
30%
Failed throttle position sensor or throttle body assembly
20%
Corroded or damaged connector at throttle body
10%
Loss of 5V reference voltage supply to throttle position sensor
5%
ECM internal fault affecting TPS circuit
Diagnostic Steps
1
Step 1: Measure throttle position sensor voltage at connector with key on, engine off
2
Step 2: Check 5V reference voltage supply and ground circuits at TPS connector
3
Step 3: Inspect connector terminals for corrosion, bent pins, or moisture intrusion
4
Step 4: Perform voltage drop test on ground circuit while wiggling harness
5
Step 5: If voltage supply and ground are good, replace throttle body assembly
Estimated Repair Cost
$150 - $700
Parts + labor, varies by vehicle and location
The throttle actuator potentiometer is reporting a signal voltage that is below the minimum acceptable threshold. This indicates either a sensor circuit issue or mechanical problem with the throttle position sensor.
The most common cause of P1543 (Throttle Actuation Potentiometer Signal too Low) is: Open circuit or short to ground in throttle position sensor wiring
Typical repair costs for P1543 range from $150 to $700, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle will likely enter limp mode with severely restricted throttle operation. May have difficulty accelerating or maintaining speed. Not safe for highway driving.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1543 to identify the root cause.
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Quick Info
Category
Powertrain
System
Electronic Throttle Control
Difficulty
Type
Manufacturer
Recommended Tools
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