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Home >> Alfa Romeo >> 2019 >> Giulia Base, AWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> 2.0L - DTCS P2AE2-00 To U148C-00 >> DTC Troubleshooting >> U1008-00-Lin 1 Bus >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    1. Turn the ignition on.
    2. With the scan tool, read PCM DTCs.

      Is this DTC active or pending?

      Yes 

      • Go To  2

      No 

  2. CHECK FOR OTHER DTCS 
    1. Refer to the recorded DTCs.

      Are there any Charge Air Cooler Coolant Pump Control circuit DTCs present?

      Yes 

      • Perform the applicable diagnostic procedure(s). Refer to DTC INDEX .

      No 

      • Go To  3
  3. CHECK THE BATTERY SUPPLY TO THE WATER PUMP RELAY BY LOAD TESTING THE CIRCUIT 
    1. Remove the Water Pump Relay from the Auxiliary B PDC.
    2. Connect the positive lead of the load test tool to terminal 30 at the Water Pump Relay connector in the Auxiliary B PDC (A). Note:  refer to the diagram below.
    3. Connect the negative lead of the load test tool to the ground circuit of the Battery or a good chassis ground.
    4. The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.
      NOTE:

      Note: Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      Note:  A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

      NOTE:

      Note: Why perform a Voltage Drop Test?  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:

      1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
      2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
      3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

      Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      GC0174938Courtesy of CHRYSLER GROUP, LLC
      NOTE:

      Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

      Is the load test bulb illuminated and bright?

      Yes 

      • Go To  5

      No 

      • Go To  4
  4. CHECK FUSE 23 IN THE PDC 
    1. Check fuse 23 (20 Amp) in the PDC for continuity.

      Is the fuse Open?

      Yes 

      • Repair the (A901) Fused B+ circuit or (F105) CAC Coolant Pump Output circuit for a short to ground and replace the fuse.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Repair the (A901) Fused B+ circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  5. CHECK THE (F105) CAC PUMP OUTPUT CIRCUIT FOR HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT 
    1. Disconnect the CAC Coolant Pump harness connector to isolate the (F105) CAC Coolant Pump Output circuit.
    2. Turn the ignition on.
    3. Connect a fused jumper between terminal 30 and terminal 87 at the Water Pump Relay connector in the Auxiliary B PDC.
    4. Connect the positive lead of the load test tool to the (F105) CAC Coolant Pump Output circuit at the CAC Coolant Pump harness connector (A). Note:  refer to the diagram below.
    5. Connect the negative lead of the load test tool to the ground circuit of the Battery or a good chassis ground.
    6. The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.
      NOTE:

      Note: Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      Note:  A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

      NOTE:

      Note: Why perform a Voltage Drop Test?  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:

      1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
      2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
      3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

      Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      GC0174938Courtesy of CHRYSLER GROUP, LLC
      NOTE:

      Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

      Is the load test bulb illuminated and bright?

      Yes 

      • Go To  6

      No 

      • Repair the (F105) CAC Coolant Pump Output circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. CHECK THE (Z101) GROUND CIRCUIT FOR HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT 
    1. The CAC Coolant Pump harness connector must be disconnected to isolate the ground circuit.
    2. Connect the positive lead of the load test tool to the (F105) CAC Coolant Pump Output circuit.
    3. Connect the negative lead of the load test tool to the (Z101) Ground circuit at the CAC Coolant Pump harness connector (A). Note:  refer to the diagram below.
    4. The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.
      NOTE:

      Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

      NOTE:

      Why perform a Voltage Drop Test?  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:

      1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
      2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
      3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

      Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      GC0174957Courtesy of CHRYSLER GROUP, LLC
      NOTE:

      Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

      Is the load test bulb illuminated and bright?

      Yes 

      • Go To  7

      No 

      • Repair the (Z101) Ground circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. CHECK THE (D407/D511) LIN BUS CIRCUIT FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Disconnect the PCM C2 harness connector.
    3. Check for continuity between ground and the (D407/D511) LIN Bus circuit at the CAC Coolant Pump harness connector.

      Is there continuity between ground and the (D407/D511) LIN Bus circuit?

      Yes 

      • Repair the (D407/D511) LIN Bus circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  8
  8. CHECK THE (D407/D511) LIN BUS CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT 
    1. Disconnect the PCM C2 harness connector.
    2. Check for continuity the (D407/D511) LIN Bus circuit and all other circuits at the PCM C2 harness connector.

      Is there continuity between the (D407/D511) LIN Bus circuit and any other circuit?

      Yes 

      • Repair the (D407/D511) LIN Bus circuit for a short to the circuit that showed continuity.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  9
  9. CHECK THE (D407/D511) LIN BUS CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the (D407/D511) LIN Bus circuit between the CAC Coolant Pump harness connector and PCM C2 harness connector.

      Is the resistance below 2.0 Ohms?

      Yes 

      • Go To  10

      No 

      • Repair the (D407/D511) LIN Bus circuit for a an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  10. REPLACE THE CHARGE AIR COOLER COOLANT PUMP AND RETEST FOR DTC 
    1. Replace the CAC Coolant Pump in accordance with the Service Information.
    2. Reconnect the CAC Coolant Pump harness connector.
    3. Reconnect the PCM C2 harness connector.
    4. Turn the ignition on.
    5. With the scan tool, erase PCM DTCs.
    6. Start the engine and allow it to idle.
    7. With the scan tool, read PCM DTCs.

      Did the DTC return as active or pending?

      Yes 

      • Go To  11

      No 

  11. CHECK RELATED PCM AND COMPONENT CONNECTIONS 
    1. Perform any Service Bulletins that apply.
    2. Disconnect all PCM harness connectors.
    3. Disconnect all related in-line harness connections (if equipped).
    4. Disconnect the related component harness connectors.
    5. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Check for spread terminals and verify proper terminal tension.

      Repair any conditions that are found.

    6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    9. With the scan tool, erase DTCs.
    10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    11. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      No 

      • The wiring or poor connection problem has been repaired.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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