The fault code P0705 is related to the transmission range sensor “B”, which is responsible for detecting the position of the gear lever in an automatic transmission. This code indicates a problem with the signal that the sensor sends to the powertrain control module (PCM) or the transmission control module (TCM).
Symptoms associated with code P0705:
- Check Engine Light illuminated.
- Noticeable loss of power, especially during acceleration from a complete stop, as the transmission starts in third gear instead of first gear. This results in slow starts and can make driving difficult.
- Erratic gear shifting or delayed gear changes.
- Disconnection of certain transmission functions, which can make driving more uncomfortable.
If you continue to drive the vehicle without performing the repair, it could lead to serious internal transmission damage, such as premature wear of internal components or complete transmission failure.
Potential causes of code P0705:
- Faulty transmission range sensor “B”:
- This sensor sends information to the PCM/TCM about the current position of the gear lever. If the sensor is faulty, it may send incorrect information, leading to abnormal transmission behavior.
- Misadjusted transmission cable/linkage:
- If the cable or linkage connecting the gear lever to the transmission is misadjusted, it can interfere with the sensor’s ability to correctly detect the transmission position.
- Damaged wiring:
- Damaged wires or connectors between the range sensor and the PCM/TCM can prevent the proper transmission of signals, causing malfunctions.
- Misadjusted range sensor:
- If the transmission range sensor “B” is misadjusted, it may not correctly detect the gear lever position and send an erroneous signal to the PCM/TCM.
- (Rarely) PCM or TCM failure:
- Although not very common, a faulty transmission control module (TCM) or powertrain control module (PCM) could be the cause of code P0705, especially if a short circuit has damaged the module.
Diagnostic and repair procedures:
- Checking wiring and connectors:
- Carefully inspect the wires and connectors between the range sensor and the PCM/TCM. Look for signs of corrosion, cuts, or disconnection. If a wire is damaged, replace it.
- Testing the range sensor:
- Use a digital voltmeter to test the sensor signal. In the KOEO (Key On, Engine Off) position, each gear position should send a distinct voltage signal. If a signal is present in multiple gear positions, it may indicate a faulty range sensor.
- Checking transmission linkage and cable:
- Check if the cable or linkage connecting the gear lever to the transmission is properly adjusted and functional. If misadjusted, readjust or repair it.
- Testing PCM/TCM failure:
- If, after checking the sensor and wiring, you suspect a PCM or TCM failure, it is important to test the module. However, the likelihood of PCM/TCM failure is low, so it is better to start by checking simpler items like the sensor and wiring.
Summary:
Code P0705 is caused by a problem with the transmission range sensor “B”, affecting the transmission’s ability to correctly detect gear lever positions. This can lead to erratic transmission behavior, such as starting in third gear, which can damage the transmission in the long term. To repair the code, check the range sensor, wiring, transmission linkage, and ensure everything is functioning correctly. If necessary, test or replace the range sensor and readjust any faulty cables or connectors.