What Does P1633 Mean?
The PCM has detected that the voltage signal from accelerator pedal position sensor 2 is below the acceptable minimum threshold. This indicates either a sensor circuit fault or internal sensor failure in the redundant APP sensor circuit.
Safety Warning
Vehicle may enter limp mode with reduced power or fail to accelerate properly, creating dangerous driving conditions especially in traffic or merging situations.
Common Causes
35%
Accelerator pedal position sensor 2 internal failure or short to ground
30%
Damaged wiring or connector pins in APP sensor 2 circuit shorted to ground
20%
Poor ground connection or corroded connector at APP sensor
10%
Water intrusion or corrosion in APP sensor connector
5%
PCM internal fault in sensor 2 voltage reference circuit
Diagnostic Steps
1
Step 1: Inspect APP sensor connector for corrosion, moisture, bent pins, and ensure secure connection
2
Step 2: Measure voltage at APP sensor 2 signal wire with key on, engine off - should read approximately 0.5-1.0V at rest
3
Step 3: Check for short to ground in APP sensor 2 signal circuit using ohmmeter with harness disconnected
4
Step 4: Monitor live data for APP sensor 2 voltage while slowly depressing pedal - should increase smoothly from ~0.5V to ~4.5V
5
Step 5: If wiring and connections are intact, replace accelerator pedal position sensor assembly
Estimated Repair Cost
$200 - $600
Parts + labor, varies by vehicle and location
The PCM has detected that the voltage signal from accelerator pedal position sensor 2 is below the acceptable minimum threshold. This indicates either a sensor circuit fault or internal sensor failure in the redundant APP sensor circuit.
The most common cause of P1633 (Accelerator Pedal Position Sensor 2 Signal Too Low) is: Accelerator pedal position sensor 2 internal failure or short to ground
Typical repair costs for P1633 range from $200 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may enter limp mode with reduced power or fail to accelerate properly, creating dangerous driving conditions especially in traffic or merging situations.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1633 to identify the root cause.
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Quick Info
Category
Powertrain
System
Electronic Throttle Control System
Difficulty
Type
Manufacturer
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