Fuel Pump Monitor / VLCM / CCRM Circuit

CCRM, VLCM and Fuel Pump Relay Applications

The Fuel Pump Monitor (FPM) circuit is spliced into the Power-To-Pump circuit and is used by the PCM for diagnostic purposes. This references pin 40 and pin 80 on the ECU/PCM. Some 2 bank ECU's that were sent in manual transmission cars, it will reference pin 79 as well.

The PCM sources a low current voltage down the FPM circuit. With the fuel pump off, this voltage is pulled low by the path to ground through the fuel pump. With the fuel pump off and the FPM circuit low, the PCM can verify that the FPM circuit and the Power-To-Pump circuit are complete from the FPM splice through the fuel pump to ground. This also confirms that the Power-To-Pump or FPM circuits are not shorted to power. With the fuel pump on, voltage is now being supplied from the Fuel Pump Relay to the Power-To-Pump and FPM circuits. With the fuel pump on and the FPM circuit high, the PCM can verify that the Power-To-Pump circuit from the Fuel Pump Relay to the FPM splice is complete. It can also verify that the fuel pump relay contacts are closed and there is a B+ supply to the Fuel Pump Relay.

The 1993-1996 Mark VIII uses a two speed fuel pump control strategy. The 1997-1998 Mark VIII use a Fuel Pump Driver Module.

In the 2-speed configuration, the fuel pump receives either B(+) voltage (High Speed Fuel Pump) or a voltage less than B(+) (Low Speed Fuel Pump). The vehicle normally runs on the low speed Fuel Pump (FP) with the high speed Fuel Pump (HFP) activated during engine start-up and high load conditions.

For low speed pump operation, the PCM grounds the Fuel Pump (FP) circuit. The VLCM receives this request for the low speed pump and activates the fuel pump output driver, sending voltage to the pump through the Power-To-Pump circuit. The Power-To-Pump circuit from the VLCM is designed so that the full (B+) voltage will not reach the pump, resulting in low speed pump operation.

For high speed pump operation, the PCM grounds the FP circuit and also sends a message through SCP (BUS(+) and BUS(-) circuits) requesting the high speed pump. With the FP circuit grounded, the VLCM activates the fuel pump output driver as in the low speed operation. With the high speed pump requested, the VLCM will also ground its HFP output closing the normally open contacts of the HFP relay. This sends full B(+) voltage to the pump resulting in high speed pump operation.

For the VLCM to operate the fuel pump at either speed, the FP circuit from the PCM must be grounded. The only exception to this is during Key On Engine Off Self-Test. During KOEO Self-Test, while the PCM has the FP output to the VLCM grounded, the PCM will request the high speed pump. The PCM will then unground the FP circuit while still requesting the high speed pump. In this situation, the VLCM will activate only the HFP output for three seconds. This allows for the isolation of faults in the high speed fuel pump secondary circuits.

Confirmation of fuel pump operation is sent from the VLCM to the PCM on the BUS(+) and BUS(-) circuits.

Fuel Pump Driver Module Applications

For 1997-1998 Mark VIII, the Fuel Pump (FP) signal is a duty cycle command sent from the Powertrain Control Module (PCM) to the Fuel Pump Driver Module (FPDM) (Table 5). The FPDM uses the FP command to operate the fuel pump at the speed requested by the PCM, or to turn the pump off.

TABLE 5—FUEL PUMP DUTY CYCLE OUTPUT FROM PCM
FP Duty Cycle Command	PCM Status	FPDM Actions
0-5%	PCM will not output this duty cycle.	Invalid FP duty cycle. FPDM will command fuel pump full on. FPDM will send 25% duty cycle signal on the Fuel Pump Monitor (FPM) circuit.
5-51%	Normal operation.	FPDM will operate the fuel pump at the speed requested. ("FP duty cycle" x 2 = pump speed % of full on (ex. FP duty cycle = 42%. 42x2=84. Pump is run at 84% of full on.)). FPDM will send 50% duty cycle signal on FPM circuit.
51-67.5%	PCM will not output this duty cycle.	Invalid FP duty cycle. FPDM will command fuel pump full on. FPDM will send 25% duty cycle signal on the Fuel Pump Monitor (FPM) circuit.
67.5-82.5%	To request the fuel pump off, the PCM will output a 75% duty cycle.	Valid fuel pump off command from PCM. FPDM will not operate the fuel pump. FPDM will send a 50% duty cycle signal on the FPM circuit.
82.5-100%	PCM will not output this duty cycle.	Invalid FP duty cycle. FPDM will command fuel pump full on. FPDM will send 25% duty cycle signal on the Fuel Pump Monitor (FPM) circuit.

**FUEL PUMP DRIVER MODULE DUTY CYCLE SIGNALS**
Duty Cycle ^a	On Time (mSec)	Comments
50%	500	"All OK" output from FPDM. With this input, the PCM can verify that the FPDM is powered and able to communicate on the FPM circuit.
25%	250	FPDM did not receive a Fuel Pump (FP) duty cycle command from the PCM, or the duty cycle that was received was invalid (refer to PCM Outputs, Fuel Pump).
75%	750	The FPDM has detected a fault in the circuits between the fuel pump and FPDM.

^aThese are the correct duty cycles for the FPM PID. If a duty cycle meter and breakout box is used, be aware that these values may be reversed depending on the trigger setting of the specific meter (for example, 25% from FPDM may read as 75% on duty cycle meter depending on trigger setting).

Also see: VLCM to CCRM Conversion Chart Below --- Requires re-pinning the VLCM Vehicle Harness Connector

NOTE: The Mark VIII uses a fan that can take the 70amp load the VLCM spits out. This load may damage the CCRM internal fan control relay or may not. You should look at a 2 speed fan to use, or use the low or high speed ran accordingly.

ALSO NOTE: Pin 45 (Low Speed Fan Control) and 46 (High Speed Fan Control) Do Not Exist in the 1996 Mark VIII ECU, so you can run a relay in line to send ground to CCRM pins 14 and 17 if you wanted to operate the fan. With A/C, Pin 41 (ACCS) exists, pin 69 (WAC) does not.

CCRM only Fan Control Operations --- With PCM control of pins 45 and 46. VLCM is not the same control from PCM.

The PCM determines engine cooling fan requirements and controls the fan operation through the Fan Control (FC) output (single speed fan applications) or the Low Fan Control (LFC) and High Fan Control (HFC) outputs as shown in Table 3. Although the FC, LFC and HFC Relays are normally open relays, the FC/LFC circuit is wired through a voltage inverter inside the CCRM. The voltage inverter ensures that the PCM must turn on (ground) the FC/LFC output to turn the fan off. This is done so the cooling fan will operate in the event of an open FC/LFC circuit.

Fan(s) Off (all speeds)- The FC/LFC output is on (grounded), opening the LFC Relay. The HFC ^aoutput is off.
Low Speed Fan On- The FC/LFC and HFC ^aoutputs are off. The FC/LFC Relay will close.
High Speed Fan On^a- The LFC output is on, opening the LFC Relay. The HFC output is also on, closing the HFC Relay.

TABLE 3—FAN STATE VERSUS HIGH AND LOW CONTROL OUTPUT
Fan State	FC/LFC Output	HFC ^aOutput
Fan OFF	on	off
Fan ON (low speed ^a)	off	off
High Speed Fan ON ^a	on	on

^a2 speed fan applications only.

1996 Mark VIII VLCM Image Below

Variable Control Relay Module (VCRM) Connector Pin Usage for up to 1996 Lincoln Mark VIII Below

Pin	Circuit	Wire Color	Application	Abbreviation
1	57	BK	Power Ground	PWR GND
2	386	LB	Power-to-Cooling Fan	Power-to-Fan
3	386	LB	Power-to-Cooling Fan	Power-to-Fan
4	37	Y	B (+) for Fan and A/C Output Driver	B (+)
5	37	Y	B (+) for Fan and A/C Output Driver	B (+)
6	37	Y	B (+) for Fuel Pump Output Driver	B (+)
7	787	PK/BK	Power-to-Fuel Pump	Power-to-Pump
10	789	BR/W	High Speed Fuel Pump Control	HFP
12	926	LB/O	Fuel Pump Control	FP
15	361	R	VPWR (for VLCM logic)	VPWR
16	570	BK/W	Ground	GND
18	348	P	Power-to-A/C Clutch	Power-to-Clutch
21	914	T/O	BUS (+)	BUS +
22	570	BK/W	Ground	GND
23	915	PK/LB	BUS (-)	BUS -

1996 Thunderbird 2V Image Below

Constant Control Relay Module (CCRM) Connector Pin Usage for 1996 2V Thunderbird Below

Pin	CKT	Wire Color	Application	Abbreviation
1	228	DB	Power to Low Speed Fan	PTLSF
2	228	DB	Power to Low Speed Fan	PTLSF
3	38	BK/O	Battery Positive	B+
4	38	BK/O	Battery Positive	B+
5	787	PK/BK	Power to Fuel Pumps	PTP
6	181	BR/O	Power to High Speed Fan	PTHSF
7	181	BR/O	Power to High Speed Fan	PTHSF
8	37	Y	Battery to EEC Relay	B+
11	175	BK/Y	Battery to Fuel Pump Relay	B+
12	361	R	Vehicle Power	VPWR
13	16	R/LG	Key Power	KEY PWR
14	197	T/O	Low Fan Control	LFC
15	57	BK	Power Ground	PWR GND
16	321	GY/W	A/C Clutch Ground	ACC GND
17	639	LG/P	High Fan Control	HFC
18	926	LB/O	Fuel Pump Control	FP
21	883	PK/LB	A/C Cycling Switch	ACCS
22	331	PK/Y	WOT A/C Cut-off	WAC
23	347	BK/Y	Power to A/C Clutch	PTAC
24	361	R	Vehicle Power	VPWR

1996 4V Mustang CCRM Image Below

Constant Control Relay Module (CCRM) Connector Pin Usage for 1996 4V Mustang Below

Pin	Circuit	Wire Color	Application	Abbreviation
1	229	R/O	Power to Fan	PTF
2	229	R/O	Power to Fan	PTF
3	38	BK/O	Battery Positive	B+
4	38	BK/O	Battery Positive	B+
5	238	DG/Y	Power to Fuel Pump	PTP
6	638	O/LB	Power to High Speed Fan	PTHSF
7	638	O/LB	Power to High Speed Fan	PTHSF
8	37	Y	Battery Positive	B+
10	37	Y	Battery Positive	B+
11	37	Y	Battery Positive	B+
12	361	R	Vehicle Power	VPWR
13	16	R/LG	Key Power	KEYPWR
14	228	DB	Low Fan Control	LFC
15	570	BK/W	Power Ground	B-
16	57	BK	A/C Clutch Ground	ACC GND
17	639	LG/P	High Fan Control	HFC
18	926	LB/O	Fuel Pump Control	FP
21	198	DG/O	A/C Cycling Switch	ACCS
22	331	PK/Y	Wide Open Throttle A/C Cut-off	WAC
23	347	BK/Y	Power to A/C Clutch	PTAC
24	361	R	Vehicle Power	VPWR

Also see the Generic Illustration

When the ignition switch is in the on position, the EEC power relay is on. The EEC Power Relay, provides power to the PCM and the fuel pump relay coil, which is inside the CCRM. Power for the fuel pump is supplied through a fuse link or high current fuse attached to the starter relay (battery side). Current flows through the Fuel Pump Relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump. The IFS is a safety device designed to shut off the fuel pump in the event of a collision (Figure 2). If the IFS is tripped, it must be reset.