Vauxhall Workshop Service and Repair Manuals

Test

Work Order Description

Nominal Value

Check: Interruption of Voltage Supply Circuit

• Ignition OFF
• Disconnect wiring harness connector from:
  Y158 Thermostat, Map-Controlled
• Ignition ON
• Measure voltage between the following terminals:
  Y158 Thermostat, Map-Controlled
  Wiring harness connector (wiring harness side) terminal (Z 16 XE1) (Z 16 XEP) 1 (Z 16 XER) (Z 18 XER) 2
  &
  Ground

greater than 11 V

greater than 11 V

Check: Short to Voltage of Signal Circuit

• Connect test lamp ( 3 W ) and multimeter in parallel and measure voltage between the following terminals:
  Y158 Thermostat, Map-Controlled
  Wiring harness connector (wiring harness side) terminal (Z 16 XE1) (Z 16 XEP) 2 (Z 16 XER) (Z 18 XER) 1
  &
  Ground

less than 0.3 V

less than 0.3 V

Check: Short to Ground of Signal Circuit

• Ignition OFF
• Disconnect wiring harness connector from:
  A84 Control Unit - Engine
  (Wiring Harness Connector (Z 16 XE1) (Z 16 XEP) XC9 (Z 16 XER) 4 (XC101) (Z 18 XER) 4 (XC3) )
• Measure resistance between the following terminals:
  Y158 Thermostat, Map-Controlled
  Wiring harness connector (wiring harness side) terminal 2
  &
  Ground

greater than 500 kOhm

greater than 500 kOhm

greater than 500 kOhm

Check: Interruption of Signal Circuit

• Measure resistance between the following terminals:
  A84 Control Unit - Engine
  Wiring harness connector (wiring harness side) terminal (Z 16 XE1) (Z 16 XEP) 55 (XC9) (Z 16 XER) 4 (XC101) (Z 18 XER) 4 (XC3)
  &
  Y158 Thermostat, Map-Controlled
  Wiring harness connector (wiring harness side) terminal 2

less than 5 Ohm

less than 5 Ohm

less than 5 Ohm

Result

Cause Of Fault

• Defective component:
  Y158 Thermostat, Map-Controlled
  or
  A84 Control Unit - Engine

Important:

Reset the concerned control unit with the diagnostic tester before replacing it. In order to do that, call up the "RESET" function from the PROGRAMMING menu of the current system on the diagnostic tester.

• Circuit interruption between:
  A84 Control Unit - Engine
  Wiring harness connector (wiring harness side) terminal (Z 16 XE1) (Z 16 XEP) 55 (XC9) (Z 16 XER) 4 (XC101) (Z 18 XER) 4 (XC3)
  &
  Y158 Thermostat, Map-Controlled
  Wiring harness connector (wiring harness side) terminal 2

• Short circuit to ground between:
  A84 Control Unit - Engine
  Wiring harness connector (wiring harness side) terminal (Z 16 XE1) (Z 16 XEP) 55 (XC9) (Z 16 XER) 4 (XC101) (Z 18 XER) 4 (XC3)
  &
  Y158 Thermostat, Map-Controlled
  Wiring harness connector (wiring harness side) terminal 2

• Short circuit to voltage between:
  A84 Control Unit - Engine
  Wiring harness connector (wiring harness side) terminal (Z 16 XE1) (Z 16 XEP) 55 (XC9) (Z 16 XER) 4 (XC101) (Z 18 XER) 4 (XC3)
  &
  Y158 Thermostat, Map-Controlled
  Wiring harness connector (wiring harness side) terminal (Z 16 XE1) (Z 16 XEP) 2 (Z 16 XER) 1 (Z 18 XER) 1

or

• Defective component:
  A84 Control Unit - Engine

Important:

Reset the concerned control unit with the diagnostic tester before replacing it. In order to do that, call up the "RESET" function from the PROGRAMMING menu of the current system on the diagnostic tester.

• Circuit interruption between:
  X125 Underhood Electronic Module
  Wiring harness connector (wiring harness side) terminal 29 (XE3)
  &
  Y158 Thermostat, Map-Controlled
  Wiring harness connector (wiring harness side) terminal (Z 16 XE1) (Z 16 XEP) 1 (Z 16 XER) (Z 18 XER) 2

or

• Defective component:
  X125 Underhood Electronic Module

Important:

Reset the concerned control unit with the diagnostic tester before replacing it. In order to do that, call up the "RESET" function from the PROGRAMMING menu of the current system on the diagnostic tester.