DTC P1477 [YF (2.0L Zetec)]


DTC P1477	Middle fan control primary circuit failure
DETECTION CONDITION	• The PCM monitors that the middle speed cooling fan relay primary circuit voltage at PCM terminal 43. The PCM detects excessive current draw (while PCM grounds circuit) or no voltage (while PCM does not ground circuit), the PCM determines that the middle speed cooling fan relay primary circuit failure.
POSSIBLE CAUSE	• Open circuit in wiring between middle speed cooling fan relay terminal 86 and PCM terminal 43 • Short to power in wiring between middle speed cooling fan relay terminal 86 and PCM terminal 43 • Short to GND in wiring between middle speed cooling fan relay terminal 86 and PCM terminal 43 • Open circuit in wiring between middle speed cooling fan relay terminal 85 and ignition switch • Damaged middle speed cooling fan relay • Damaged PCM


STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2	VERIFY REPAIR INFORMATION AVAILABILITY • Verify related service repair information availability. • Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	INDETIFY TRIGGER DTC FOR FREEZE FRAME DATA • Is DTC P1477 on FREEZE FRAME DATA?	Yes	Go to the next step.
3		No	Go to FREEZE FRAME DATA DTC inspection. (See DTC TABLE [YF (2.0L Zetec)].)
4	INSPECT MIDDLE SPEED FAN CONTROL (MFC) CIRCUIT FOR INTERMITTENT FAILURE • Rerun KOEO, KOER self test and Continuous Memory DTCs. • Is DTC P1477 present in Continuous Memory self test only?	Yes	Go to Step 10.
4		No	Go to the next step.
5	CHECK VPWR VOLTAGE TO MFC RELAY • Disconnect appropriate fan control relay. • Turn the ignition switch to ON. • Measure VPWR circuit voltage at middle speed cooling fan control relay harness connector terminal 85. • Is voltage greater than 10.5 V?	Yes	Go to the next step.
5		No	Repair open circuit, then go to Step 12.
6	CHECK FOR MFC CIRCUIT CYCLING • Turn the ignition switch to ON. • Connect a non-powered test lamp between VPWR circuit and the MFC circuit at middle speed cooling fan control relay harness connector terminal 85 to 86. • Access Output Test Mode HFC PID on the WDS or equivalent. • While observing test lamp, command the HFC PID on and off. • Does the test lamp turned on and off when the cooling fan output is commanded on and off?	Yes	Replace middle speed cooling fan control relay, then go to Step 12.
6		No	Go to the next step.
7	CHECK MFC CIRCUIT FOR SHORT TO POWER IN HARNESS • Disconnect PCM. • Turn the ignition switch to ON. • Measure voltage between middle speed cooling fan control relay terminal 86 at harness side connector and ground. • Is voltage less than 1.0 V?	Yes	Go to the next step.
7		No	Repair short circuit, then go to Step 12.
8	CHECK MFC CIRCUIT FOR SHORT TO GROUND HARNESS • Disconnect WDS or equivalent to DLC-2. • Measure resistance between middle speed cooling fan control relay terminal 86 at harness side connector and ground. • Is resistance greater than 10.0 ohms?	Yes	Go to the next step.
8		No	Repair short to ground circuit, then go to Step 12.
9	CHECK FOR OPEN MFC CIRCUIT • Measure the resistance of the MFC circuit between the PCM terminal 43 and middle speed cooling fan control relay connector terminal 85 at harness side connector. • Is resistance less than 5.0 ohms?	Yes	Replace PCM, then go to Step 12.
9		No	Repair open circuit, then go to Step 12.
10	CHECK MFC CIRCUIT FOR OPEN OR SHORT TO POWER • A/C and defroster off. • Disconnect cooling fan connector (both applications with two fans). • Connect a non-powered test lamp between (MIDDLE) FAN PWR circuit and ground circuit at the cooling fan harness connector (either one for applications with two fans). • Turn the ignition switch to ON. • Access Output Test Mode MFC PID on the WDS or equivalent. • Command HFC PID to on. • Observe test lamp for an indication of a fault while completing the following (the lamp will turn off when a fault is detected, indicating an open or short to power supply): - Shake wiggle and bend the MFC circuit between PCM and middle speed cooling fan control relay. - Shake wiggle and bend the VPWR circuit to the middle speed cooling fan control relay - Lightly tap on the middle speed cooling fan control relay to simulate road shock • Is fault indicated?	Yes	Isolate fault and repair, repair or replace malfunctioning part. Then go to Step 12.
10		No	Go to the next step.
11	CHECK MFC CIRCUIT FOR SHORT TO GND • Turn the ignition switch to ON. • Command HFC PID to off using Output Test Mode on the WDS or equivalent. • Observe the test lamp for an indication of a fault while completing the following (the lamp will turn on when a fault is detected, indicating MFC circuit short to ground): - Shake wiggle and bend the MFC circuit between PCM and middle speed cooling fan control relay. - Lightly tap on the middle speed cooling fan control relay to simulate road shock • Is fault indicated?	Yes	Isolate fault and repair, repair or replace malfunctioning part. Then go to the next step.
11		No	Intermittent concern exists, go to Intermittent Troubleshooting Procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING [YF (2.0L Zetec)].)
12	VERIFY TROUBLESHOOTING OF DTC P1477 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the WDS or equivalent. • Perform KOEO/KOER self test. (See KOEO/KOER SELF-TEST [YF (2.0L Zetec)].) • Is the PENDING CODE same DTC present?	Yes	Replace PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [YF (2.0L Zetec)].)
12		No	Go to the next step.
13	VERIFY AFTER REPAIR PROCEDURE • Perform "After Repair Procedure". (See AFTER REPAIR PROCEDURE [YF (2.0L Zetec)].) • Is there any DTC present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [YF (2.0L Zetec)].)
13		No	Troubleshooting completed.