Symptoms
Symptoms of a DTC P2800 may include:
- Illumination of the malfunction indicator light (MIL) with DTC code set P2800
- Backup lights may not work
- It may be necessary to move the shift lever slightly up and down for better contact to allow the starter to engage and start the engine.
- It may be impossible to engage the starter
- In some cases, the engine only starts in neutral
- May start in any gear
- Irregular shift RPMs
- Decreased fuel economy
- The transmission may show delayed engagement
- Toyota vehicles, including trucks, may display erratic instrument readings
Potential Causes
Causes
of this DTC may include:
- TRS “B” is loose and poorly adjusted
- The transmission range sensor “B” is faulty
- Bad connector to the external TRS “B”, loose, corroded, or bent pins
- Wiring harness shorted to the external sensor due to rubbing on the transmission linkage
- Blockage in the TRS port of the internal valve body or faulty sensor
Diagnostic Steps
and Possible Solutions
Replacing an internal TRS requires using a Tech II for diagnosis, followed by draining the transmission and removing the pan. The sensor is located at the bottom of the valve body, which is responsible for all transmission functions. The sensor is continuously immersed in hydraulic fluid, which causes housing issues. Often, hydraulic flow is restricted or the O-ring has caused the problem.
In any case, this is a complicated process best left to a transmission specialist.
Replacing External Transmission Range Sensors:
- Block the wheels and set the parking brake.
- Place the transmission in neutral
- Locate the transmission shift linkage. On front-wheel drive vehicles, it will be located on top of the transaxle. On rear-wheel drive vehicles, it will be on the driver’s side
Remove the electrical connector from the TRS sensor and inspect it carefully. Look for corroded, bent, or pushed back (missing) pins in the sensor. Check the connector on the harness for the same, but in this case, there are female ends that must be in place. The harness connector can be replaced separately if it cannot be saved by cleaning or straightening the female connectors. - Apply a small amount of dielectric grease to the connector before reconnecting
- Look at the wiring harness location and ensure it is not rubbing on the shift linkage. Check for broken or shorted wires due to lack of insulation
- Check that the sensor is not loose. If it is loose, set the parking brake and the transmission in neutral. Turn the key and rotate the TRS until the backup lights come on. At this point, tighten the two TRS bolts. If the vehicle is a Toyota, you must rotate the TRS until a 5 mm drill bit fits into the housing hole before tightening it
Remove the nut holding the shift lever and lift the lever - Remove the electrical connector from the sensor
- Remove the two bolts securing the sensor to the transmission. Unless you want to practice magic and turn this ten-minute job into several hours, do not drop the two bolts into no man’s land
- Lift the sensor from the transmission
- Look at the new sensor and ensure the markings on the shaft and housing, where it is marked “neutral,” are aligned
- Install the sensor on the shift lever shaft and install and tighten the two bolts
- Plug in the electrical connector
- Reinstall the shift lever and tighten the nut
- Additional note: The external TR sensor found on some Fords may be referred to as an MLPS or manual lever position sensor.
Related Transmission Range Sensor Codes: P2801, P2802, P2803, and P2804.