Saturday, June 25, 2011

transmission will not shift down

The shifter cable broken or It can be faulty governor sensor:--

the governor pressure sensor and typically replacing the sensor fixes the problem. The sensor is in the transmission so the pan will need to be removed so replace the filter at the same time.

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If you have access to a scan to here is the test to help figure out the problem your having.

Monitor the shift solenoid status on the scan tool when driving to see what the PCM appears to be electrically commanding to determine if this problem is an electrical control issue, or an internal transmission failure.
In second gear, the PCM will activate (turn ON) all 3 shift solenoids.
When shifting to 3rd gear, the PCM will deactivate (turn OFF) all 3 shift solenoids below 16 MPH. Above 16 MPH it will turn Shift Solenoid #1 (SS1) ON.
When attempting to command a shift into overdrive, the PCM will turn Shift Solenoid #3 (SS3) ON.

If the PCM is not electrically commanding 3rd and 4th gear during the condition, verify that the throttle position (TP) sensor, the Transmission Range (TR) sensor and the Vehicle speed sensor (VSS) are all providing proper input to the PCM before replacing it.

The TR sensor should provide the PCM a battery voltage signal when the shift lever is placed in the overdrive gear shift position.
When the shift lever is in the drive (3) position, the PCM should get a battery voltage input signal on the Brown/Yellow (BR/Y) wire at pin 9.
These two circuits should not have a voltage feed when the shift lever is in any other position.

The TP sensor should indicate 06-1.0 volt at closed throttle and sweep upwards as expected as the throttle is gradually opened.