Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. Turn the ignition on.
2. Wait 15 seconds with the ignition on and then start the engine. Allow the vehicle to warm up to operating temperature.
3. With a scan tool, read and record DTCs on the repair order.
  Is the DTC active or pending?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK THE VOLTAGE SUPPLY TO THE RADIATOR FAN RELAYS IN THE PDC
NOTE:
It is important to remember that on a vehicle equipped with A/C, the PCM uses the Low Speed Rad Fan Control circuit to control the Radiator Fan 1 Low Speed and the Radiator Fan 2 Control Relays simultaneously. Therefore, in order for a fault to set due to a faulty relay or missing voltage supply to the relay coil, both relays must be faulty or missing the voltage supply to the coils. If either one of the relays is functional, this fault will not set.
1. Turn the ignition off.
2. Remove the Radiator Fan 1 Relay from the PDC.
3. Remove the Radiator Fan 2 Relay from the PDC.
4. Turn the ignition on.
5. Using a 12-volt test light connected to ground, probe terminal 30 at the Radiator Fan 1 Relay connector and Radiator Fan 2 Relay connector in the PDC.
  NOTE:
  The test light should be illuminated and bright for both. Compare the brightness to that of a connection to direct battery.
  
  Is the test light illuminated and bright?
  
  Yes
  - Go To 3
  No
  - Check for any open fuses in the PDC. If a fuse is open, check the output circuits for a short to ground and repair as necessary. Also, severely dragging or binding Fan Motors can cause an open fuse as well. If the fuses are good, diagnose and repair the reason for no Battery voltage to the Radiator Fan 1 Relay and Radiator Fan 2 Relay in the PDC and perform the appropriate repair.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE RADIATOR FAN RELAY (N112) CONTROL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
3. Check for continuity between ground and the Radiator Fan Relay (N112) Control circuit at the Radiator Fan 1 Relay connector.
  Is there continuity between ground and the Radiator Fan Relay (N112) Control circuit?
  
  Yes
  - Repair the Radiator Fan Relay (N112) Control circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 4
CHECK THE RADIATOR FAN RELAY (N112) CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
CAUTION:
Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.
1. Reconnect the PCM C1 harness connector with the adapter connected in-line.
  (special tool #10436, Adapter, GPEC Diagnostic)
2. Measure the resistance of the Radiator Fan Relay (N112) Control circuit between the Radiator Fan 1 Relay connector in the PDC and the GPEC Adaptor.
3. Measure the resistance of the Radiator Fan Relay (N112) Control circuit between the Radiator Fan 2 Relay connector in the PDC and the GPEC Adaptor.
  Is the resistance below 3.0 Ohms for both relays?
  
  Yes
  - Go To 5
  No
  - Repair the Radiator Fan Relay (N112) Control circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE RADIATOR FAN RELAYS
1. Install the Radiator Fan Relays back into the PDC.
2. Reconnect the PCM C1 harness connector
3. Turn the ignition on, engine not running.
4. Using a 12 volt test light connected to ground, back probe the Radiator Fan 2 Control Relay (N112) Control circuit.
5. Grounding the (N112) control circuit should close both relays in the PDC.
  Do both Radiator Fan Relays energize when the control circuit is grounded?
  
  Yes
  - Go To 6
  No
  - Replace the Radiator Fan Relays.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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
  - Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .