Pinpoint Test I: Insufficient Heat During Engine Idle - 3.9L Engine

WARNING: This page is about a different car, the 2004 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.

I1 CARRY OUT THE DATC MODULE SELF-TEST
- Key in ON position.
- Carry out the DATC module self-test and retrieve continuous DTCs. Refer to CLIMATE CONTROL SYSTEM . Record the DTCs displayed, if any.
- Are any DTCs displayed?
  1. Yes : REFER to DUAL ELECTRONIC AUTOMATIC TEMPERATURE CONTROL (DATC) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX . CARRY OUT the necessary diagnosis and REPAIR as necessary.
  2. No : GO to I2.
I2 RECHECK DATC MODULE CONFIGURATION
- Enter Module Identification mode.
- Enter the following diagnostic mode on the diagnostic tool: PIDCNFG Data.
- Does the data read 4N_3N_2Y?
  1. Yes : GO to I3.
  2. No : RECONFIGURE the DATC module.
I3 CHECK THE COOLANT LEVEL
- Check the coolant level with the engine at hot and cold temperatures.
- Is the engine coolant at the correct level (hot and cold)?
  1. Yes : GO to I4.
  2. No : REFILL the system and PRESSURE TEST for leaks. In addition, if the coolant level had dropped below the "MIN" level, SET the system to MAX heat and RUN the engine at 3,000 RPM for 3 to 5 minutes until hot air blows from the outlets. RECHECK coolant level. GO to I4.
I4 CHECK FOR AUXILIARY COOLANT PUMP OPERATION
- Connect the diagnostic tool.
- Key in ON position.
- In the active command mode, request Climate Control System and select Pump/VCB or set driver side temperature to 32°C (90°F).
- Can the auxiliary cooling pump be heard running or be felt running?
  1. Yes : System is operating correctly.
  2. No : GO to I5.
I5 CHECK THE AUXILIARY PUMP MOTOR
- Key in OFF position.
- Disconnect: Auxiliary Coolant Pump C163.
- Key in ON position.
- Make sure the active command Pump/VBC is still selected or the driver side temperature is set to 32°C (90°F).
- Measure the voltage between auxiliary coolant pump C163, circuit 30S-FB1 (RD/YE), harness side and circuit 31-FB1 (BK), harness side.
  
  Fig 1: Measuring Voltage Between Auxiliary Coolant Pump C163 Circuit
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
  1. Yes : INSPECT terminals for damage and correct installation. If pins are installed correctly, INSTALL a new auxiliary coolant pump. TEST the system for normal operation.
  2. No : GO to I6.
I6 CHECK CIRCUIT 31-FB1 (BK) FOR AN OPEN
- Measure the resistance between auxiliary coolant pump C163, circuit 31-FB1 (BK), harness side and ground.
  
  Fig 2: Measuring Resistance Between Auxiliary Coolant Pump C163, Circuit 31-FB1 (BK), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
  1. Yes : GO to I7.
  2. No : REPAIR circuit 31-FB1 (BK). TEST the system for normal operation.
I7 CHECK THE AUXILIARY COOLANT PUMP RELAY
- Key in OFF position.
- Disconnect: Auxiliary Coolant Pump Relay C1005.
- Measure the voltage between CJB auxiliary coolant pump relay pins 2 and 5, circuit 30-FA74A (RD), harness side and ground.
  
  Fig 3: Measuring Voltage Between CJB Auxiliary Coolant Pump Relay Pins 2 And 5, Circuit 30-FA74A (RD), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
  1. Yes : GO to I8.
  2. No : REPAIR circuit 30-FA74A (RD). TEST the system for normal operation.
I8 CARRY OUT THE RELAY COMPONENT TEST
- Carry out the relay component test.
  Refer to SYSTEM WIRING DIAGRAMS for schematic and connector information.
- Is the relay OK?
  1. Yes : GO to I9.
  2. No : INSTALL a new auxiliary coolant pump relay. TEST the system for normal operation.
I9 CHECK CIRCUIT 30S-FB1 (RD/YE) FOR AN OPEN
- Disconnect: Auxiliary Coolant Pump Relay C1005.
- Measure the resistance between auxiliary coolant pump C163, circuit 30S-FB1 (RD/YE), harness side and auxiliary coolant pump relay pin 3, circuit 30S-FB1 (RD/YE), harness side.
  
  Fig 4: Measuring Resistance Between Auxiliary Coolant Pump C163, Circuit 30S-FB1 (RD/YE), Harness Side
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
  1. Yes : GO to I10.
  2. No : REPAIR circuit 30S-FB1 (RD/YE). TEST the system for normal operation.
I10 CHECK THE DATC MODULE
- Key in OFF position.
- Connect: Auxiliary Coolant Pump Relay C1005.
- Connect: Auxiliary Coolant Pump C163.
- Disconnect: DATC Module C228a.
- Disconnect: DATC Module C228b.
- Connect a fused jumper wire between DATC module C228b-18, circuit 91S-FA76 (BN/BU), harness side and DATC module C228a-2, circuit 31-FA10 (BK), harness side.
  
  Fig 5: Connecting Fused Jumper Wire Between DATC Module C228B-18, Circuit 91S-FA76 (BN/BU), Harness Side
  Courtesy of FORD MOTOR CO.
- Does the auxiliary coolant pump motor operate?
  1. Yes : INSPECT all connectors and terminals, RECONNECT the connectors, and TEST the system for normal operation. If condition still exists, INSTALL a new DATC module. TEST the system for normal operation.
  2. No : GO to I11.
I11 CHECK CIRCUIT 91S-FA76 (BK/OG) FOR A SHORT TO POWER
NOTE: If a short to power is found, it is necessary to install a new DATC module.
- Disconnect: Auxiliary Coolant Pump Relay C1005.
- Measure the voltage between auxiliary coolant pump relay pin 2, circuit 91S-FA76 (BK/OG), harness side and ground.
  
  Fig 6: Measuring Voltage Between Auxiliary Coolant Pump Relay Pin 2, Circuit 91S-FA76 (BK/OG), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
  1. Yes : REPAIR circuit 91S-FA76 (BK/OG). INSTALL a new DATC module. TEST the system for normal operation.
  2. No : GO to I12.
I12 CHECK CIRCUIT 91S-FA76 (BK/OG) FOR AN OPEN
- Measure the resistance between auxiliary coolant pump relay circuit 91S-FA76 (BK/OG), harness side and DATC module C228b-18, circuit 91S-FA76 (BK/OG), harness side.
  
  Fig 7: Measuring Resistance Between Auxiliary Coolant Pump Relay Circuit 91S-FA76 (BK/OG), Harness Side
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
  1. Yes : INSPECT all connectors and terminals, RECONNECT the connectors and TEST the system. If condition still exists, INSTALL a new DATC module. TEST the system for normal operation.
  2. No : REPAIR circuit 91S-FA76 (BK/OG). TEST the system for normal operation.