Chrysler PT Cruiser 2001 Service Manual Supplement page 2605

Symptom:
P0703-BRAKE SWITCH SENSE CIRCUIT
When Monitored and Set Condition:
P0703-BRAKE SWITCH SENSE CIRCUIT
When Monitored: With the engine running. The PCM expects the signal to be high for 16
cycles while it monitors the brake switch signal during accel and decel modes.
Set Condition: After the vehicle speed increases, the PCM must accumulate 6 seconds
while delta throttle voltage is above 0.02 volts. The count is reset to zero whenever the
brake switch indicates a low signal.
BRAKE LAMP SWITCH GROUND CIRCUIT OPEN
BRAKE LAMP SWITCH SENSE CIRCUIT OPEN
POWERTRAIN CONTROL MODULE (BRAKE SENSE)
BRAKE LAMP SWITCH (SENSE CIRCUIT)
BRAKE LAMP SWITCH SENSE CIRCUIT SHORT TO GROUND
TEST
1 Turn the ignition off.
Disconnect the Brake Lamp Switch harness connector.
Measure the resistance between ground and the Brake Lamp Switch Ground circuit.
Is the resistance below 5.0 ohms?
Yes → Go To 2
→ Repair the Brake Lamp Switch Ground circuit for an open.
No
2 Turn the ignition off.
Disconnect the Brake Lamp Switch harness connector.
Disconnect the PCM harness connectors.
Measure the resistance of the Brake Lamp Switch Sense circuit.
Is the resistance below 5.0 ohms?
Yes → Go To 3
→ Repair the Brake Lamp Switch Sense circuit for an open.
No
3 Turn the ignition off.
Disconnect the Brake Lamp Switch harness connector.
Measure the resistance between the Brake Lamp Switch Sense terminal and the
Ground terminal (measurement taken across switch).
Apply and release the Brake Pedal while monitoring the ohmmeter.
Does the resistance change from below 5.0 ohms to open circuit?
Yes → Go To 4
→ Replace the Brake Lamp Switch.
No
POSSIBLE CAUSES
ACTION
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
DRIVEABILITY - GAS
145
APPLICABILITY
All
All
All