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Operation Pride
Automatic Transmission Diagnostics - Electrical Symptoms
Model: 1995-97 Range Rover
CAUSE
Signal from TCM to ECM being sent for too long or outside normal limits.
REPAIR
Check the following connectors for any sign of loose connectors or terminals backing out.
ECM connector C507 pin 31.
TCM connector C601 pin 32.
In-line connectors C551 pin 4 and C659 pin 9.
CODE: 24 FRSS, Output speed sensor, signal out of range
EFFECT: Limp home in third or fourth
DESCRIPTION
This fault is only tested during a downshift and therefore the engine must be in a forward gear, i.e.
D, 3, 2. If the engine speed is above a defined threshold during the shift for a duration of 50 ms or
more, then the fault will flagged.
Erratic, harsh, or elongated shifts can be a result of this fault.
CAUSE
The output speed sensor provides the information necessary for the TCM to calculate the pressure
needed for any shift and also for the length of the shift. The TCM compares the engine speed to
output speed for a measure of slip.
Mechanical slip due to excessive internal wear on the clutches can also cause a large difference
between engine speed input and output speed.
REPAIR
Check the continuity of the wiring from the TCM to the transmission connector and also the resis-
tance of the output speed sensor.
See figure 1 for assistance with the transmission connector pinouts and resistance of the output
speed sensor.
Verify the mechanical condition of the transmission and check transmission fluid for contamination.
CODE: 26 FT_T, Engine torque signal out of range
EFFECT: Poor shift quality - Maximum pressure on shifts
DESCRIPTION
The ECM provides the TCM with an indication of the torque the engine is currently producing. In-
correct information can affect both the timing and the length of the shifts. The torque signal is also
needed to determine the amount of torque reduction required by the TCM for smooth shifts.
Erratic, harsh or elongated shifts can result.