Symptom:
IMPROPER GEAR
When Monitored and Set Condition:
IMPROPER GEAR
When Monitored:
Engine RPM greater than 450 and output speed (ABS) greater than
180 RPM. No Input Speed sensor N2 - N3, Shift lever, and/or ABS wheel speed DTCs
present.
Set Condition:
The TCM compares the calculated gear with the gear the transmission
has actually engaged. If the actual gear differs from the gear calculated by the TCM, the
TCM value is adjusted to the engaged gear and a counter is increased by 2. If after a shift
the engaged gear and the calculated gear still match , the counter is decreased by 1 point.
A DTC is detected as soon as the counter exceeds a threshold. If the fault is detected 3
consecutive ignition cycles the transmission will be placed in Limp-in and the MIL
activated.
POSSIBLE CAUSES
ABS DTCS PRESENT
SOLENOID DTCS PRESENT
INTERNAL TRANSMISSION
TCM - IMPROPER GEAR
TEST
ACTION
APPLICABILITY
1
NOTE: Low fluid level can be the cause of many transmission problems. If
the fluid level is low locate and repair the leak then check and adjust the
fluid level per the service information.
NOTE: Always perform diagnostics with a fully charged battery to avoid
false symptoms.
With the DRBIII
t, read the engine DTCs. Check and repair all engine DTCs prior to
performing transmission symptom diagnostics.
With the DRBIII
t, read and record all Transmission DTCs.
NOTE: Check connectors - Clean/repair as necessary. Poor pin to terminal
connections can set DTCs.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
Repair as necessary.
Most DTCs set on start up but some must be set by driving the vehicle such that all
diagnostic monitors have run.
Note: Verify flash level of transmission controller. Some problems are
corrected by software upgrades to the transmission controller.
NOTE: Check for any Technical Service Bulletins that may apply.
Perform this procedure prior to Symptom diagnosis.
All
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TRANSMISSION - NAG1