System Diagram
System Description
The headlamp system for Canada vehicles is equipped with a daytime light relay that activates the high beam headlamps at approximately half illumination whenever the engine is running. If the parking brake is depressed before the engine is started, the daytime lights will not be illuminated. The daytime lights will illuminate once the parking brake is released. Thereafter, the daytime lights will continue to operate when the parking brake is depressed.
Component Parts Location
Component Description
After starting the engine with the parking brake released and the lighting switch in the OFF or 1ST position, the headlamp high beam automatically turns on. With the lighting switch in the 2nd position or with autolamps ON, the headlamps function the same as conventional light systems.
OPERATION
The BCM monitors inputs from the parking brake switch and the combination switch (lighting and turn signal switch) to determine when to activate the daytime light system. The BCM sends a daytime light request to the IPDM E/R via the CAN communication lines. The IPDM E/R grounds the daytime light relay which in turn, provides power to the ground side of the RH high beam lamp. Power flows backward through the RH high beam lamp to the IPDM E/R, through the high beam fuses, through the LH high beam lamp circuit to the LH high beam lamp and on to ground. The high beam lamps are wired in series which causes them to illuminate at a reduced intensity.
When starting the engine with the parking brake depressed, the daytime lights will not operate.
P0128 thermostat function
DTC Logic
DTC DETECTION LOGIC
NOTE:
If DTC P0128 is displayed with DTC P0300, P0301, P0302, P0303, P0304, P0305 or
P0306, first perform
the trouble diagnosis for DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306.
Engine coolant temperature has not risen enough to open the thermostat even ...
U1000 CAN comm circuit
Description
DTC Logic
DTC DETECTION LOGIC
NOTE:
U1000 can be set if a module harness was disconnected and reconnected, perhaps
during a repair. Confirm
that there are actual CAN diagnostic symptoms and a present DTC by performing
the Self Diagnostic Result
procedure.
Diagnosis Proc ...
v DLC and HVAC circuit
Diagnosis Procedure
1.CHECK HARNESS CONTINUITY (OPEN CIRCUIT)
Turn the ignition switch OFF.
Disconnect the battery cable from the negative terminal.
Disconnect the following harness connectors.
ECM
A/C auto amp.
Check the continuity between the data link connector and the A/C ...