What Does P0990 Mean?
DTC P0990 indicates the transmission fluid pressure sensor/switch "E" is reporting a voltage above the maximum threshold expected by the TCM. This high-signal condition typically indicates an open circuit in the sensor wiring, a failed sensor with an open element, or a short to the reference voltage. The TCM will use default pressure values which may result in suboptimal shift quality.
Common Causes
30%
Open circuit in the pressure sensor "E" signal or ground wire
30%
Failed pressure sensor with an internally open sensing element
20%
Short to reference voltage (5V) in the signal wire harness
15%
Disconnected or backed-out terminal at the sensor connector
5%
TCM input pull-up fault holding the signal line high
Diagnostic Steps
1
Read live data for pressure sensor "E" to confirm the voltage is at or near the reference voltage (typically ~5V), consistent with a high-circuit condition.
2
Inspect the sensor connector for disconnected, pushed-back, or corroded terminals.
3
With the sensor connected, measure voltage at the sensor signal pin; then jumper the signal pin to the sensor ground pin and see if the scan tool reading drops, confirming the circuit path to the TCM is intact.
4
Measure continuity of the sensor ground wire from the sensor connector back to the TCM to rule out an open ground path.
5
Replace the pressure sensor if the sensor itself is confirmed open; clear codes and verify correct pressure readings across gear changes.
Estimated Repair Cost
$120 - $550
Parts + labor, varies by vehicle and location
DTC P0990 indicates the transmission fluid pressure sensor/switch "E" is reporting a voltage above the maximum threshold expected by the TCM. This high-signal condition typically indicates an open circuit in the sensor wiring, a failed sensor with an open element, or a short to the reference voltage...
The most common cause of P0990 (Transmission Fluid Pressure Sensor/Switch "E" Circuit High) is: Open circuit in the pressure sensor "E" signal or ground wire
Typical repair costs for P0990 range from $120 to $550, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A perpetually high pressure reading may cause the TCM to reduce line pressure, leading to clutch slippage during shifts. Sustained slippage generates excessive heat and can cause rapid transmission damage if not addressed.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0990 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission
Difficulty
Type
Generic (SAE)
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