TEST
ACTION
APPLICABILITY
1
NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
While observing the PRIM BRAKE SWITCH status on the DRB display, press and
release the brake pedal several times.
Does the DRB display PRIM BRAKE SWITCH: PRESSED and RELEASED for the
appropriate pedal position?
All
Yes
→ Go To 2
No
→ Go To 11
2
Turn the ignition on.
While observing the SEC BRAKE SWITCH status on the DRB display, press and
release the brake pedal several times.
Does the DRB display SEC BRAKE SWITCH: PRESSED and RELEASED for the
appropriate pedal position?
All
Yes
→ Go To 3
No
→ Go To 4
3
WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?
All
Yes
→ Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No
→ Test Complete.
4
Turn the ignition off.
Disconnect the Brake Lamp Switch harness connector.
Turn the ignition on.
Measure the voltage between the Secondary Brake Switch Signal circuit and ground.
Is the voltage above 9.0 volts?
All
Yes
→ Go To 5
No
→ Go To 8
163
DRIVEABILITY - DIESEL
P0703-BRAKE SWITCH SIGNAL CIRCUITS PLAUSIBILITY WITH RE-
DUNDANT CONTACT —
Continued