No Start Lincoln Town Car II

No Start

1. IFS switch circuit open or not reset.
2. Open circuit in or between PCM and fuel pump.
3. Faulty ground connection at fuel pump.
4. Faulty fuel pump.

If engine starts, go to step 11). If engine does not start, go to step 15).

11) Check Fuel Pump Operation Turn ignition on. Wait 5 seconds. Listen for fuel pump operation. If fuel pump is off, go to step 13). If fuel pump is on, go to step 12).

12) Check For Fuel Pump Relay Always Closed Turn ignition off. Disconnect fuel pump relay. Turn ignition on. If fuel pump is off with relay disconnected, replace fuel pump relay and repeat QUICK TEST. If fuel pump is on with relay disconnected, repair short to power in POWER-TO-PUMP or FPM circuit. (For models with relay block, also check fuel pump prime plug circuit). Repeat QUICK TEST.

13) Check Continuity Of Fuel Pump Monitor (FPM) Circuit Turn ignition off. Disconnect PCM 60-pin connector. Inspect and repair any damaged terminals. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Disconnect fuel pump relay. Measure resistance between test pin No. 8 at breakout box and POWER-TO-PUMP circuit at fuel pump relay wiring harness connector. If resistance is less than 5 ohms, go to step 25) (dual HO2S) or replace PCM and repeat QUICK TEST (single HO2S). If resistance is 5 ohms or more, repair open circuit and repeat QUICK TEST.

Note. A break in step numbering sequence occurs at this point. Procedure skips from step 13) to step 15). No test procedures have been omitted.

15) Check IFS Switch Turn ignition off. Disconnect fuel pump IFS switch. Ensure switch is reset. Measure resistance of IFS switch. If resistance is less than 5 ohms, check for open in POWER-TO-PUMP circuit, poor fuel pump ground or faulty fuel pump. If resistance is 5 ohms or more, reset or replace IFS switch. Repeat QUICK TEST.

Note. A break in step numbering sequence occurs at this point. Procedure skips from step 15) to step 20). No test procedures have been omitted.

20) Code 96/543 Code 96/543 indicates fuel pump secondary circuit failure between B+ circuit and FPM connection to POWER-TO-PUMP circuit. Following are possible causes

1. Open circuit between B+ and FPM connection to POWER-TO-PUMP circuit.
2. Fuel pump relay contacts are always open.

1. HO2S short to power (dual HO2S models).
2. Faulty PCM.

If engine starts, go to step 25) (dual HO2S) or replace PCM and repeat QUICK TEST (single HO2S). If engine does not start, go to step 21).

21) Check For B+ To Fuel Pump Relay Turn ignition off. Disconnect fuel pump relay. Measure voltage between B+ terminal at fuel pump relay wiring harness connector and negative battery terminal. If voltage is 10.5 volts or more, go to step 22). If voltage is less than 10.5 volts, check fuse/fusible link. If fuse/fusible link is okay, repair open circuit in B+ circuit. Repeat QUICK TEST.

22) Check POWER-TO-PUMP Circuit Continuity Turn ignition off. Leave fuel pump relay disconnected. Measure resistance between POWER-TO-PUMP terminal at fuel pump relay wiring harness connector and negative battery terminal. If resistance is less than 10 ohms, replace fuel pump relay and repeat QUICK TEST. If resistance is 10 ohms or more, repair open circuit in POWER-TO-PUMP circuit between FPM junction and fuel pump relay. Repeat QUICK TEST.

Note. A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 25). No test procedures have been omitted.

Due to internal circuitry of PCM, a left/front HO2S signal short to power could produce a Code 95/542 or 96/543.

25) Check Left/Front HO2S Sensor For Short To Power Turn ignition off. Disconnect left or front HO2S sensor. Measure resistance between HO2S SIGNAL terminal and KEY POWER terminal at HO2S sensor wiring harness connector. If resistance is 10,000 ohms or more, go to step 26). If resistance is less than 10,000 ohms, replace HO2S sensor. Clear KAM, and repeat QUICK TEST.

HO2S Sensor Connector. Scheme 59

HO2S Sensor Wiring Harness Connector. Scheme 60

26) Check HO2S Circuit For Short To Power Turn ignition off. Leave left or front HO2S sensor disconnected. Disconnect PCM. Inspect and repair any damaged terminals. Turn ignition on. Measure voltage between HO2S SIGNAL at HO2S wiring harness connector and chassis ground. If voltage is less than 2 volts, replace PCM and repeat QUICK TEST. If voltage is 2 volts or more, repair short circuit. Clear KAM, and repeat QUICK TEST.

Note. A break in step numbering sequence occurs at this point. Procedure skips from step 26) to step 90). No test procedures have been omitted.

90) Continuous Memory Code 95/542 Code 95/542 indicates one of the following conditions

1. Faulty ground circuit at fuel pump.
2. FPM or POWER-TO-PUMP circuit short to power.
3. IFS switch not reset.
4. Fuel pump relay contacts stuck closed.
5. Open circuit in or between fuel pump and FPM circuit at PCM.
6. Left or front HO2S circuit short to power (dual HO2S system).
7. FUEL PUMP circuit is activated at a time that is not programmed into PCM strategy.
8. Engine stall due to excessive load.

Start engine. Check for engine miss or intermittent fuel pump deactivation while performing following

1. Shake and bend POWER-TO-PUMP circuit wiring harness connector between fuel pump relay and fuel pump.
2. Shake and bend fuel pump ground circuit between fuel pump and ground.
3. Lightly tap fuel pump to simulate road shock.
4. Lightly tap IFS switch to simulate road shock.

Turn ignition off. Check harness connectors for corrosion and damage. Isolate and repair any faults. Clear continuous memory, and repeat QUICK TEST. If no faults are found, go to step 91).

91) Check FPM Circuit Turn ignition off. Disconnect PCM 60-pin connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Connect test light between test pin No. 8 and test pin No. 37 at breakout box. With test light lit, perform wiggle test on FPM circuit between fuel pump and PCM. Light will go out if fault is found, indicating an open circuit. If a fault is found, repair as necessary and repeat QUICK TEST. If no fault is found, go to step 92).

92) Check For Shorts To Power Connect a test light between breakout box test pin No. 8 and test pin No. 40. Test light should be off. Observe test light while bending and shaking FPM circuit and POWER-TO-PUMP circuit. Lightly tap fuel pump relay to simulate road shock. Fault is indicated if test light comes on. Isolate and repair fault as necessary, and repeat QUICK TEST. If no fault is found, go to step 96) (dual HO2S) or step 99) (single HO2S).

93) Continuous Memory Code 96/543: Check For Continuous Memory Code 87/556 If Code 87/556 is present, go to step 95). If Code 87/556 is not displayed, go to step 94).

94) Check EEC-IV Harness A Continuous Memory Code 96/543, without an accompanying Continuous Memory Code 87/556, indicates one of the following conditions has occurred during vehicle operation

1. An open in B+ circuit between B+ and fuel pump relay.
2. Fuel pump relay contacts open.
3. Open in POWER-TO-PUMP circuit between fuel pump relay to FPM splice (if applicable).
4. Left/front HO2S circuit short to power (dual HO2S).

Start engine. Check for engine miss or intermittent fuel pump deactivation while performing the following

1. Shake and bend B+ circuit wiring harness between power source and fuel pump relay.
2. Shake and bend POWER-TO-PUMP circuit wiring harness connector between fuel pump relay and FPM splice (if applicable).
3. Lightly tap fuel pump relay to simulate road shock.

Turn ignition off. Inspect all fuel pump relay and B+ connectors for damage and corrosion. If fault is found, repair as necessary and repeat QUICK TEST. If no fault is found, a Continuous Memory Code 95/543 may have been set without a Continuous Memory Code 87/556, even though a fault has occurred in fuel pump primary circuit. Go to step 95) for fuel pump primary circuit check.

95) Continuous Memory Code 87/556: Check EEC-IV Harness A Continuous Memory Code 87 or 556 indicates primary fuel pump circuit has failed during vehicle operation. Possible causes for this fault are

1. Open in VPWR circuit between EEC power relay and fuel pump relay.
2. Open coil in fuel pump relay.
3. Open in fuel pump circuit (pin No. 22).
4. Faulty IFS switch.

Start engine. Check for engine miss or intermittent fuel pump deactivation while performing the following

1. Shake and bend VPWR circuit wiring harness between EEC and fuel pump relay.
2. Shake and bend FP circuit wiring harness connector between fuel pump relay and PCM.
3. Lightly tap fuel pump relay to simulate road shock.
4. Lightly tap IFS switch to simulate road shock (if equipped).

Turn ignition off. Disconnect PCM 60-pin connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. If fault is found, isolate and repair as necessary. Repeat QUICK TEST. If no faults are found but Code 96/543 is found, go to step 96) (dual HO2S). If fault cannot be duplicated at this time, go to step 99) (all others).

Due to internal circuitry of PCM, an intermittent left/front HO2S signal short to power could produce a Continuous Memory Code 95/542 or 96/543.

96) Check Left/Front HO2S Circuit For Short To Power Turn ignition off. Breakout box should be installed with PCM disconnected. Connect test light between left/front HO2S test pin and pin No. 40 at breakout box. See CIRCUIT TEST H for left/front HO2S test pin identification. Test light should be off. Observe test light while bending and shaking left/front HO2S circuit from HO2S sensor to PCM. Lightly tap HO2S SENSOR to simulate road shock. Fault is indicated if test light comes on. Isolate and repair as necessary. Clear Keep-Alive Memory (KAM), and repeat QUICK TEST. If no fault is indicated, go to step 99).

Note. A break in step numbering sequence occurs at this point. Procedure skips from step 96) to step 99). No test procedures have been omitted.

99) Road Test Vehicle Purpose of this test is to identify faults by monitoring certain controlled parameters while trying to recreate a drive-ability or MIL symptom. To prepare for road test

1. Install fuel pressure gauge and if available, a MAP/BARO tester.
2. Disconnect PCM 60-pin connector, install breakout box and reconnect PCM to breakout box.
3. Connect "T" vacuum gauge into manifold vacuum line.
4. Have DVOM, writing materials and appropriate schematics and pin voltage charts available.

With ignition on and negative lead of DVOM connected to negative battery terminal, ensure following signals are correct

1. POWERS: KAPWR (pin No. 1) is greater than 10.5 volts, VPWR (pins No. 37 and 57) is greater than 10.5 volts and VREF (pin No. 26) is 4-6 volts.
2. GROUNDS: PWR GND (pins No. 40 and 60), SIG RTN (pin No. 46) and IGN GND (pin No. 16) are 0.0-0.5 volt.
3. OPTIONAL GROUNDS: HO2S GND (pin No. 49), CSE GND (pin No. Step 20) and MAF RTN (pin No. 9 or 15) are 0.0-0.5 volt.

Test lights and DVOM are useful during diagnosis. For example: with Continuous Memory Code 87/556 (fuel pump primary circuit failure) and a surge or stall symptom, connect a test light to fuel pump relay between VPWR and ground. Connect DVOM between FP circuit at fuel pump relay and breakout box test pin No. 1. Under normal driving conditions, test light will be on and DVOM will read battery voltage. If vehicle stalls, PCM will open FP circuit and DVOM voltage will be low. If fault is in fuel pump circuit, test light and DVOM status will change as fault occurs. If test light at VPWR circuit goes out, fault is in VPWR circuit to fuel pump relay. If test light and DVOM status do not change and Continuous Memory Code 87/556 is set again, replace fuel pump relay. If only FP voltage goes low, fault is in FP circuit or PCM. To diagnose FP circuit and PCM, connect DVOM between breakout box test pin No. 1 and 22. If voltage goes low as symptom occurs, replace PCM. If voltage stays high as symptom occurs, fault is in FP circuit. For fuel pump secondary circuit Codes 95/542 and 96/543, circuits B+, POWER-TO-PUMP and FPM can be diagnosed using same procedure. Drive vehicle and attempt to induce symptom. Information provided by vehicle operator may help when trying to recreate symptom. When symptom occurs, assistant should observe and record changes in voltage signals. Information about symptom and operating condition value of voltage signal and any other information available should be recorded for analysis. If unable to duplicate symptom during road test, verifyEEC-IV values are within acceptable range. After test is completed, analyze results to locate and repair fault causing symptom. If problem cannot be identified, go to TESTS W/O CODES article in this sectionfor other possible causes of symptom.

Perform this test when instructed by QUICK TEST. To prevent replacement of good components, be aware the following non-EEC related areas may be at fault

1. Damaged vacuum hoses.
2. Damaged EGR Pressure Transducer (EPT).
3. EGR valve.

This test is only intended to diagnose

1. EGR Vacuum Regulator (EVR) solenoid.
2. PCM.
3. Wiring harness circuits (EVR and VPWR).

EVR solenoid regulates vacuum to EGR valve by way of EVT. When energized, EVR opens a port between manifold vacuum and EGR valve. When not energized, EVR closes port to EGR and vacuum is vented to atmosphere.

EGR Valve Regulator (EVR) Solenoid Circuits Terminals. Scheme 61

1) Code 558 Code 558 indicates failure in EVR solenoid circuit. Possible causes for this fault are

1. Faulty EVR solenoid.
2. Faulty vacuum hoses.
3. Open or ground circuit in wiring harness.
4. Faulty Powertrain Control Module (PCM).

Turn ignition off. Remove scan tester (if applicable). Disconnect cruise control servo wiring harness connector. Connect DVOM negative lead to STO terminal at Data Link Connector (DLC). Connect positive lead to positive battery terminal. Install a jumper wire between STI terminal and SIG RTN terminal at DLC. (Scheme 28)-22. Perform KOEO SELF-TEST until continuous memory test is complete. DVOM will read less than 1.0 volt when test is complete to indicate PCM has entered OUTPUT STATE CHECK. Depress and release throttle. If voltage does not increase, fully apply throttle and release. If STO voltage remains low, go to CIRCUIT TEST QC. If voltage increases, remain in OUTPUT STATE CHECK and go to step 2).

2) Check EVR Solenoid Electrical Turn ignition off. Remove EVR solenoid wiring harness connector. Connect DVOM positive lead to VPWR terminal and negative test lead to EVR terminal at EVR solenoid wiring harness connector. Depress and release throttle 3-5 times to cycle solenoid output. If EVR solenoid voltage output change is 0.5 volt or more, go to step 3). If EVR solenoid voltage output change is less than 0.5 volt, go to step 5).

3) Check EVR Solenoid Vacuum Turn ignition on. Disconnect EVR solenoid vacuum hoses. Install vacuum pump on EVR solenoid vacuum port. Install vacuum gauge on solenoid output port. Apply 6 in. Hg, and hold. Depress and release throttle 3-5 times to cycle solenoid output. Turn ignition off. If vacuum gauge shows vacuum cycling at output port, go to step 4). If vacuum gauge does not show vacuum cycling at output port, replace EVR solenoid and repeat QUICK TEST.

4) Check EVR Vacuum Hoses Remove jumper wire, vacuum pump and gauge. Remove vacuum hoses individually. Plug one end of hose. Connect vacuum pump at opposite end. Apply vacuum and observe gauge. If vacuum is not held, replace hose and repeat QUICK TEST. If vacuum is held, ensure vacuum port between EPT and EGR is not restricted. If vacuum port is clear, go to step 5).

5) Check EVR Solenoid VPWR Turn ignition off. Disconnect EVR solenoid wiring harness connector. Turn ignition on. Measure voltage between VPWR terminal at wiring harness connector and negative battery terminal. If voltage is 10.5 volts or more, go to step 6). If voltage is less than 10.5 volts, repair open VPWR circuit and repeat QUICK TEST.

6) Check EVR Solenoid Circuit Continuity Turn ignition off. Disconnect PCM 60-pin connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between EVR terminal at EVR solenoid wiring harness connector and test pin No. 33. If reading is less than 5 ohms, go to step 7). If resistance is 5 ohms or more, repair open circuit and repeat QUICK TEST.

7) Check EVR Solenoid Circuit For Short Turn ignition off. Leave EVR solenoid disconnected. Measure resistance between test pin No. 33 and test pins No. 37 and 57 at breakout box. Measure resistance between test pin No. 33 and test pins No. 40, 46 and 60 at breakout box. If each resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST. If reading is less than 10,000 ohms, repair short circuit and repeat QUICK TEST.

CANP valve is controlled by the PCM. CANP valve is used to regulate the flow of fuel vapors from the EVAP canister to the fuel system. The CANP valve operates on manifold vacuum and a duty cycle from the PCM.

Perform this test when instructed by QUICK TEST. This test is only intended to diagnose

1. CANP valve.
2. Faulty Powertrain Control Module (PCM).
3. Wiring harness circuits (CANP and VPWR).

CANP Valve Schematic. Scheme 62

Identifying CANP Valve Circuit & Connector Terminals. Scheme 63

1) Code 565 Code 565 indicates failure in CANP valve. Possible causes for this fault are

1. Faulty CANP valve.
2. Faulty vacuum hoses.
3. Open or ground circuit in wiring harness.
4. Faulty Powertrain Control Module (PCM).

Turn ignition off. Remove scan tester (if applicable). Disconnect cruise control servo wiring harness connector (if equipped). Connect DVOM negative lead to STO terminal at Data Link Connector (DLC). Connect positive lead to positive battery terminal. Install a jumper wire between STI terminal and SIG RTN terminal at DLC. (Scheme 28)-23. Perform KOEO SELF-TEST until continuous memory test is complete. DVOM will read less than 1.0 volt when test is complete to indicate PCM has entered OUTPUT STATE CHECK. Fully apply and release throttle. If voltage does not increase, fully apply throttle and release. If voltage remains low, fully apply and release throttle. If voltage does not increase, go to CIRCUIT TEST QC. If voltage increase can be obtained, remain in OUTPUT STATE CHECK and go to step 2).

2) Check CANP Valve Electrical Turn ignition off. Remove CANP valve wiring harness connector. Connect DVOM positive lead to VPWR terminal and negative test lead to CANP terminal at CANP valve wiring harness connector. Depress and release throttle 3-5 times to cycle voltage output. If voltage output change is 0.5 volt or more, go to step 3). If EVR solenoid voltage output change is less than 0.5 volt, go to step 7).

3) Measure CANP Valve Resistance Leave ignition off and CANP valve connectors disconnected. Measure resistance between connector terminals. If resistance is not 30-36 ohms, replace CANP valve and repeat QUICK TEST. If resistance is 30-36 ohms, go to step 4).

4) Check CANP Valve For Vacuum Leaks Leave CANP valve connectors disconnected. Remove vacuum hose from input port of CANP valve. Using a vacuum pump, apply 16 in Hg. to input port. Replace valve if it does not hold vacuum for 20 seconds. If valve holds vacuum for 20 seconds, got to next step.

5) Check CANP Valve Electrical/Mechanical Reconnect Leave CANP valve connector. Ensure 16 in Hg. is applied to input port. Fully apply and release throttle. If vacuum is not released, replace CANP valve and repeat QUICK TEST. If vacuum is released, remove jumper wire between SIG RTN and STI terminals of DLC. Go to next step.

6) Check Vacuum At CANP Valve Input Port Leave CANP valve wiring harness connected. Start engine and allow to idle. Remove CANP valve vacuum input hose. If vacuum is not present at hose, check hose for blockage, leaking or incorrect routing. If vacuum is present at hose, EEC system is okay. Testing is complete.

7) Check VPWR Circuit Voltage Leave CANP valve wiring harness disconnected. Turn ignition on. Measure voltage CANP valve wiring harness connector terminal VPWR and battery ground. If 10.5 volts or more is present, go to next step. If less than 10.5 volts is present, repair open circuit and repeat QUICK TEST.

8) Check CANP Circuit Continuity Turn ignition off. Disconnect PCM 60-pin connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pin No. 11 and CANP terminal of CANP valve wiring harness connector. If either reading is 5 ohms or more, repair open circuit and repeat QUICK TEST. If both readings are less than 5 ohms, go to step 9).

9) Check For CANP Circuit Short To Power Leave ignition off and CANP valve connector disconnected. Measure resistance between breakout box test pin No. 11 and pins No. 37 and 57. If any reading is less than 10,000 ohms, repair short circuit and repeat QUICK TEST. If all readings are 10,000 ohms or more, go to next step.

10) Check For Short To Ground Leave ignition off and CANP valve connector disconnected. Measure resistance between breakout box test pin No. 11 and pins No. 40, 46 and 60. If any reading is less than 10,000 ohms, repair short to ground and repeat QUICK TEST. If all readings are 10,000 ohms or more, replace PCM and repeat QUICK TEST.