7A1–44 TRANSMISSION CONTROL SYSTEM (4L30–E)
DTC P0719/Flashing Code 77 TCC Brake Switch Circuit High (Stuck On)
D07RX019
Circuit Description
The brake switch is used to indicate brake pedal status.
The normally opened brake switch signal voltage circuit is
opened.
Brake switch supplies a B+ signal on circuit RED to the
PCM, when the brakes are applied. The PCM uses this
signal to deenergize the TCC solenoid when the brakes
are applied.
This DTC detects a closed brake switch during
accelerations. This is a type “D” DTC.
Conditions For Setting The DTC
D
No OSS DTCs P0722 or P0723.
D
The PCM detects a closed brake switch/circuit (12
volts) for 2 seconds, and the following events occur
seven consecutive times: vehicle speed is less than 8
km/h (5 mph); then vehicle speed is between 8 and 32
km/h (5 and 20 mph) for 4 seconds; then vehicle
speed is greater than 32 km/h (20 mph) for 4 seconds.
Action Taken When The DTC Sets
D
If throttle opening is greater than 10% and vehicle
speed is greater than 45 km/h (28 mph), then
disregard brake switch contingency for TCC off
mode.
D
The PCM will not illuminate CHECK TRANS Lamp.
Conditions For Clearing The DTC
D
The DTC can be cleared from the PCM history by
using a scan tool.
D
The DTC will be cleared from history when the vehicle
has achieved 40 warm–up cycles without a failure
reported.
D
The PCM will cancel the DTC default actions when
the fault no longer exists and the ignition is cycled “off”
long enough to power down the PCM.
Diagnostic Aids
D
Inspect the wiring for poor electrical connections at
the PCM and brake switch. Look for possible bent,
backed out, deformed or damaged terminals. Check
for weak terminal tension as well. Also check for a
chafed wire that could short to bare metal or other
wiring. Inspect for a broken wire inside the insulation.
D
When diagnosing for a possible intermittent short or
open condition, move or massage the wiring harness
while observing test equipment for a change.
D
Check customer driving habits and/or unusual driving
conditions (i.e. stop and go, highway).
D
Check brake switch for proper mounting and
adjustment.
Test Description
The numbers below refer to the step numbers on the
diagnostic chart:
2. This test checks for voltage at the brake switch.
5. This test checks the brake switch.
8. This test checks circuit RED at the PCM.