Diagnostic Aids

Perform this test only when instructed during QUICK TEST or if directed by other test procedures. This test is only intended to diagnose the following:

• Wiring Harness Circuits (VPWR & HCF)
• Hydraulic Cooling Fan Solenoid/Pump Assembly. See Fig 1.
• Powertrain Control Module (PCM)

Fig 1: Identifying Hydraulic Cooling Fan Solenoid/Pump

Courtesy of FORD MOTOR CO.

NOTE: Perform test step  1) when directed from ELECTRIC COOLING FAN DOES NOT OPERATE or ELECTRIC COOLING FAN ALWAYS ON symptom under SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V - CNG & GASOLINE article.
1. 1) DTC P1474 Or Cooling Fan Problems: Check HCF Solenoid Resistance
   DTC P1474 is set when PCM detects voltage too high or too low when compared to expected voltage range on HCF primary circuit. Possible causes are:
   • HCF Circuit Open, Or Shorted To Ground Or Power
   • Faulty HCF Solenoid
   • Faulty PCM

   Turn ignition switch to OFF position. Disconnect HCF solenoid connector. Using a DVOM, measure resistance between HCF solenoid connector terminals. If resistance is 8.5-11.5 ohms, go to next step. If resistance is not 8.5-11.5 ohms, replace HCF solenoid assembly.

2. 2) Check VPWR Voltage To HCF Solenoid
   
   Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and HCF solenoid connector VPWR terminal. See Fig 2. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open in VPWR circuit.
   Fig 2: Identifying Hydraulic Cooling Fan Solenoid Circuit & Connector Terminals

   Courtesy of FORD MOTOR CO.
3. 3) Check HCF Circuit For Open In Harness
   
   Turn ignition switch to OFF position. Disconnect PCM connector "C". Using a DVOM, measure resistance of HCF circuit between PCM harness connector terminal No. C36 and HCF solenoid harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in HCF circuit.
4. 4) Check HCF Circuit For Short To Power In Harness
   
   Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and PCM harness connector terminal No. C36. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to VPWR in HCF circuit.
5. 5) Check HCF Circuit For Short To Ground In Harness
   
   Turn ignition switch to OFF position. Disconnect scan tool from DLC. Using a DVOM, measure resistance between chassis ground and PCM harness connector terminal No. C36 (HCF circuit). If resistance is more than 10 k/ohms, replace PCM. If resistance is 10 k/ohms or less, repair short to ground in HCF circuit.