TEST
ACTION
APPLICABILITY
8
Turn the ignition on.
Connect one end of a jumper wire to ground and back probe the A/C Pressure Signal
circuit at the ECM harness connector.
With the DRB, select Engine, Bosch Controller then Inputs/Outputs.
Read the A/C H/L Press Sw status.
Does the DRB display A/C H/L Press Sw ON?
All
Yes
→
Go To
9
No
→
Replace and program the ECM in accordance with the Service
Information.
Perform ROAD TEST VERIFICATION - VER-2.
9
Disconnect the A/C High Pressure Switch harness connector.
Turn the ignition on.
Connect one end of a jumper wire to ground and back probe the A/C Pressure Signal
circuit at the A/C High Pressure Switch harness connector.
With the DRB, select Engine, Bosch Controller then Inputs/Outputs.
Read the A/C H/L Press Sw status.
Does the DRB display A/C H/L Press Sw ON?
All
Yes
→
Go To
10
No
→
Repair the A/C Pressure Signal circuit for an open between the
ECM and the A/C High Pressure Switch.
Perform ROAD TEST VERIFICATION - VER-2.
10
Turn the ignition off.
Disconnect the A/C High Pressure Switch harness connector.
Measure the resistance of the A/C High Pressure Switch.
Is the resistance below 10.0 ohms?
All
Yes
→
Go To
11
No
→
Replace the A/C High Pressure Switch.
Perform ROAD TEST VERIFICATION - VER-2.
11
Disconnect the A/C Low Pressure Switch harness connector.
Turn the ignition on.
Connect one end of a jumper wire to ground and the other end to the A/C Pressure
Sense circuit at the A/C Low Pressure Switch harness connector.
With the DRB, select Engine, Bosch Controller then Inputs/Outputs.
Read the A/C H/L Press Sw status.
Does the DRB display A/C H/L Press Sw ON?
All
Yes
→
Go To
12
No
→
Repair the A/C Pressure Sense circuit for an open between the
A/C High Pressure Switch and the A/C Low Pressure Switch.
Perform ROAD TEST VERIFICATION - VER-2.
12
Turn the ignition off.
Disconnect the A/C Low Pressure Switch harness connector.
Measure the resistance of the A/C Low Pressure Switch.
Is the resistance below 10.0 ohms?
All
Yes
→
Repair the ground circuit at the A/C Low Pressure Switch for an
open.
Perform ROAD TEST VERIFICATION - VER-2.
No
→
Replace the A/C Low Pressure Switch.
Perform ROAD TEST VERIFICATION - VER-2.
159
DRIVEABILITY - DIESEL
*CHECKING THE A/C SYSTEM —
Continued