Content .. 1008 1009 1010 1011 ..
Chevrolet Silverado / GMC Sierra. Manual - part 1010
RANGE SELECTOR DISPLAYS INCORRECT RANGE
Torque converter diagnosis
TCC does not apply
TCC does not release
TCC apply/release quality
Apply (300 RPM Slip).
Refer to No Torque Converter Clutch
Release.
Refer to Torque Converter Clutch
Shudder.
Indicator On or Message Center Displays
Message:
This category contains the following topics:
Message Center displays "change trans fluid"
Refer to Transmission Component and
System Description.
If symptom is not found
Refer to Transmission Fluid Check.
Refer to Road Test.
Refer to Line Pressure Check.
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
Fig. 1: Range Selector Schematic
Courtesy of GENERAL MOTORS CORP.
CIRCUIT DESCRIPTION
The transmission range (TR) switch is part of the park/neutral position (PNP) and back-up lamp
switch assembly, which is externally mounted on the transmission manual shaft. The TR switch
contains four internal switches that indicate the transmission gear range selector lever position.
The transmission control module (TCM) supplies ignition voltage to each switch circuit. As the
gear range selector lever is moved, the state of each switch may change, causing the circuit to
open or close. An open circuit or switch indicates a high voltage signal. A closed circuit or switch
indicates a low voltage signal. The TCM detects the selected gear range by deciphering the
combination of the voltage signals. The TCM compares the actual voltage combination of the
switch signals to a TR switch combination chart stored in memory.
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
DIAGNOSTIC AIDS
Refer to Transmission Range Switch Logic table for valid combinations of switch signal
circuits A, B, C and Parity. On the table, HI indicates an ignition voltage signal. LOW indicates a
zero voltage signal.
TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
4: By disconnecting the TR switch, the ground path of all TR switch circuits is removed and
the TCM should recognize all circuits as open. The scan tool should display HI for all range
signal states.
5: This step tests the TR switch wiring for an open or the lack of the signal voltage from the
TCM.
6: This step tests the TR switch wiring and the TCM by providing a ground path through a
fused jumper wire. When grounded, the scan tool range signal states should change to LOW.
7: This step tests the TR switch wiring and the TCM by providing a ground path through a
fused jumper wire. When grounded, the scan tool range signal states should change to LOW.
8: This step tests the TR switch wiring and the TCM by providing a ground path through a
fused jumper wire. When grounded, the scan tool range signal states should change to LOW.
9: This step tests the TR switch wiring and the TCM by providing a ground path through a
fused jumper wire. When grounded, the scan tool range signal states should change to LOW.
Range Selector Displays Incorrect Range
Step
Action
Values
Yes
No
1
1. Install a scan tool.
2. Turn ON the ignition, with the
engine OFF.
3. Select TR Sw. on the scan tool.
4. With the scan tool, observe the TR
Sw. display while selecting each
transmission range: P, R, N, D4, D3,
D2 and D1.
Does each selected transmission range
match the scan tool TR Sw. display?
-
Go to Step 2 Go to Step 3
Go to Testing
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
2
Observe the IPC gear range display while
selecting each transmission range: P, R, N,
D4, D3, D2, D1.
Does each selected transmission range
match the IPC display?
-
for
Intermittent
Conditions
and Poor
Connections
Go to Step
16
3
With the scan tool, observe the TR Sw.
A/B/C/P display.
Does the scan tool TR Sw. A/B/C/P
parameter indicate HI for all range signal
states?
-
Go to Step 13 Go to Step 4
4
1. Turn OFF the ignition.
2. Disconnect the TR switch 4-way
connector.
3. Turn ON the ignition, with the
engine OFF.
Does the scan tool TR Sw. A/B/C/P
parameter indicate HI for all range signal
states?
-
Go to Step 5
Go to Step
10
5
1. Using the DMM and the J 35616
GM Terminal Test Kit, measure the
voltage from the transmission range
signal A circuit of the TR switch
connector to ground.
2. Measure the voltage from the
transmission range signal B circuit of
the TR switch connector to ground.
3. Measure the voltage from the
transmission range signal C circuit of
the TR switch connector to ground.
4. Measure the voltage from the
transmission range signal P circuit of
the TR switch connector to ground.
Does the voltage measure within the
specified range at all 4 circuits?
10-12 V
Go to Step 6
Go to Step
11
Connect a fused jumper wire from the TR
switch connector, signal circuit A, to
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
Content .. 1008 1009 1010 1011 ..