What Does P2803 Mean?
The PCM has detected an abnormally high voltage signal from the Transmission Range Sensor 'B' circuit. The signal voltage exceeds the maximum threshold expected for any valid gear position.
Common Causes
35%
Shorted transmission range sensor B circuit to voltage/power source
25%
Failed transmission range sensor B with internal short to power
20%
Damaged or chafed wiring harness shorting signal wire to battery voltage
12%
Corroded connector causing voltage feedback or cross-circuit contamination
8%
TCM/PCM internal fault causing excessive voltage output
Diagnostic Steps
1
Step 1: Disconnect TR sensor B connector and measure voltage on signal wire at harness side; should drop to 0V if shorted in harness
2
Step 2: If voltage remains high with sensor disconnected, trace wiring for short to power source
3
Step 3: If voltage drops to normal, reconnect sensor and backprobe signal wire; monitor voltage through all gear positions
4
Step 4: Check for proper reference voltage supply (not excessive) at TR sensor connector
5
Step 5: Replace TR sensor B if testing indicates internal sensor short; verify repair with scan tool data
Estimated Repair Cost
$190 - $520
Parts + labor, varies by vehicle and location
The PCM has detected an abnormally high voltage signal from the Transmission Range Sensor 'B' circuit. The signal voltage exceeds the maximum threshold expected for any valid gear position.
The most common cause of P2803 (Transmission Range Sensor "B" Circuit High) is: Shorted transmission range sensor B circuit to voltage/power source
Typical repair costs for P2803 range from $190 to $520, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Transmission may enter fail-safe mode limiting available gears. Vehicle may not properly recognize Park position, affecting starting and park brake release logic.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2803 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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