Symptom:
P1790-FAULT IMMEDIATELY AFTER SHIFT
When Monitored and Set Condition:
P1790-FAULT IMMEDIATELY AFTER SHIFT
When Monitored:
After a speed ratio error is stored.
Set Condition:
This DTC is set if the associated speed ratio DTC is stored within 1.3
seconds after a shift.
POSSIBLE CAUSES
FAULT AFTER SHIFT
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 Engine DTC’s. Check and repair all Engine DTC’s prior to
performing any transmission symptom diagnostics.
With the DRBIII
t, read Transmission DTC’s. Record all DTC’s and 1 Trip Failures.
NOTE: Diagnose 1 Trip Failures as a fully matured DTC.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
Repair as necessary.
Perform the Shift Lever Position Test. If the test does not pass, refer to Symptom test
for P0706 Check Shifter Signal.
For Gear Ratio DTC’s, check and record all CVI’s.
Most DTC’s 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 Powertrain Control Module. Some problems are
corrected by software upgrades to the Transmission and Engine software.
NOTE: Check for applicable TSB’s related to the problem.
Perform this procedure prior to Symptom diagnosis.
All
Continue
Go To
2
2
This test is set along with a gear ratio DTC. Perform the appropriate test for the Gear
Ratio DTC stored.
NOTE: Check 1 trip failures if there are no gear ratio DTCs current.
If there are no possible causes remaining, view repair.
All
Repair
Refer to the Transmission category and perform the appropriate
symptom.
Perform 40/41TE (NGC) TRANSMISSION VERIFICATION
TEST - VER 1.
166
TRANSMISSION - NGC