DTC P0724 Brake Switch Circuit High
Input 3.8L
The brake switch
indicates brake pedal status to the powertrain
control module (PCM). The brake switch is a normally-closed switch that
supplies battery voltage on circuit 420 to the PCM. Applying the brake
pedal opens the switch, interrupting voltage to the PCM. When the brake pedal
is released, the PCM receives a constant voltage signal. If the PCM receives a
zero voltage signal at the brake switch input, and the torque converter clutch
(TCC) is engaged, the PCM de-energizes the TCC solenoid valve. The PCM
disregards the brake switch input for TCC scheduling if there is a brake switch
circuit fault.
When the PCM detects a
closed brake switch circuit (12 volts, high input) during decelerations,
then DTC P0724 sets. DTC P0724 is a type C DTC.
Conditions
for Running the DTC
- No VSS assembly DTCs P0502 or P0503.
- The ignition is ON.
Conditions
for Setting the DTC
The PCM detects a closed
brake switch circuit (12 volts) without changing for 2 seconds and
the following events occur eight times:
- The vehicle speed is greater than
32 km/h (20 mph) for 6 seconds;
- then the vehicle speed is between 8-32 km/h
(5-20 mph) for 4 seconds;
- then the vehicle speed is less than
8 km/h (5 mph).
Action
Taken When the DTC Sets
- The PCM does not illuminate the
malfunction indicator lamp (MIL).
- The PCM records the operating
conditions when the Conditions for Setting the DTC are met. The PCM stores
this information as Failure Records.
- The PCM stores DTC P0724 in PCM
history.
Conditions
for Clearing the DTC
- A scan tool can clear the DTC.
- The PCM clears the DTC from PCM
history if the vehicle completes 40 warm-up cycles without a
non-emission-related diagnostic fault occurring.
- The PCM cancels the DTC default
actions when the fault no longer exists and/or the ignition switch is OFF
long enough in order to power down the PCM.
- Inspect the connectors at the PCM,
the brake switch and all other circuit connecting points for an
intermittent condition. Refer to Testing
for Intermittent and Poor Connections in Wiring Systems.
- Inspect the circuit wiring for an
intermittent condition. Refer to Testing
for Electrical Intermittents in Wiring
Systems.
- Ask about the customer's driving
habits. Ask about unusual driving conditions (e.g. stop and go,
expressway, etc.).
- Inspect the brake switch for proper
mounting and operation.
- Inspect for AB
The numbers below refer
to the step numbers on the diagnostic table.
|
DTC P0724 Brake Switch Circuit High Input (3.8L) Step |
Action |
Value(s) |
Yes |
No |
|
Did
you perform the Powertrain Diagnostic System Check?
|
-- |
Go to A
Powertrain On Board Diagnostic (OBD) System Check
in Engine Controls |
||
Important Before
clearing the DTC, use the Scan Tool in
order to record the Failure Records. Using the Clear Info function erases the
Failure Records from the PCM.
Did
the TCC Brake Switch status change from Closed to Open? |
-- |
|||
|
Replace
the brake switch. Refer to Stoplamp Switch Replacement in Hydraulic Brakes. Did
you complete the replacement? |
-- |
-- |
||
|
Test
input circuit (CKT 420) of the brake switch for a short to power. Refer
to Circuit
Testing and Wiring
Repairs in Wiring Systems. Did you find and correct the condition? |
-- |
|||
|
Replace
the PCM. Refer to PCM
Replacement/Programming in Engine Controls. Did you complete the
replacement? |
-- |
-- |
||
|
Perform
the following procedure in order to verify the repair:
Has
the test run and passed? |
-- |
System OK |