Engine Starts

• Short to power in fuel pump/FPM circuit.
• High speed fuel pump (HFP) relay contacts stuck closed.
• Short to ground in hfp circuit (VCRM terminal No. 10).
• Open FPM circuit between PCM and power-to-fuel pump splice.
• Short to power in left heated oxygen sensor (HO2S).
• Damaged VCRM.
• Damaged PCM.

Check if engine will start and idle for one minute. If engine starts and idles for one minute, go to next step. If engine does not start or starts but does not idle for one minute, go to step 130).

121) Verify Fuel Pump Is Off  Turn ignition on, and wait 5 seconds. Listen for motor noise from fuel pump. If fuel pump is off, go to step 126). If fuel pump is on, go to next step.

122) Check VCRM  Turn ignition off. Disconnect and inspect VCRM connector. Clean or repair connector as necessary. Turn ignition on. Listen for fuel pump noise. If fuel pump is off, turn ignition off. Replace VCRM. Reconnect all components. Repeat QUICK TEST. If fuel pump is on, turn ignition off and go to step 123).

123) Check HFP Relay & Circuits  Turn ignition off. Ensure VCRM is disconnected. Disconnect HFP relay. Relay is located in engine compartment fuse block. Turn ignition on. Listen to fuel pump. If fuel pump is off, go to next step. If fuel pump is on, turn ignition off. Repair short to power in power-to-fuel pump/FPM circuit. Reconnect all components. Repeat QUICK TEST.

124) Check For Short To Ground In HFP Circuit  Turn ignition off. Ensure VCRM and HFP relay are disconnected. Measure resistance between negative battery terminal and terminal No. 10 (Brown/White wire) at VCRM connector. If resistance is more than 10,000 ohms, replace HFP relay. Reconnect all components. Repeat QUICK TEST. If resistance is 10,000 ohms or less, repair short to ground in HFP circuit. Reconnect all components. Repeat QUICK TEST.

126) Check FPM Circuit Continuity  Turn ignition off. Disconnect and inspect PCM connector. Clean or repair connector as necessary. Install breakout box. Leave PCM disconnected. Disconnect HFP relay. Measure resistance between test pin No. 8 at breakout box and power-to-fuel pump terminal (Pink/Black wire) at HFP relay connector. See Fig 1 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in FPM circuit between PCM and splice to power-to-fuel pump circuit. Remove breakout box, and reconnect all components. Repeat QUICK TEST  .

Fig 1: High Speed Fuel Pump (HFP) Relay Conn. Terminal ID (XB4)

127) Check For Short To Power In Left HO2S  Turn ignition off. Disconnect left HO2S. Measure resistance between HO2S SIGNAL terminal and KEY POWER terminal at HO2S connector. See Fig 2 . If resistance is more than 10,000 ohms, to next step. If resistance is 10,000 ohms or less, replace HO2S. Reconnect all components. Repeat QUICK TEST.

Fig 2: Heater Oxygen Sensor (HO2S) Terminal ID (XB5)

128) Check For Short To Power In Left HO2S Circuit  Turn ignition off. Ensure left HO2S is disconnected. Disconnect and inspect PCM connector. Clean or repair connector as necessary. Turn ignition on. Measure voltage between negative battery post and HO2S SIGNAL terminal (Red/Black wire) at harness side of HO2S connector. See Fig 2 . If voltage is less than 2 volts, replace PCM. Reconnect all components. Repeat QUICK TEST. If voltage is 2 volts or more, repair short to power in left HO2S circuit.

130) Check Inertia Fuel Shutoff (IFS) Switch  Turn ignition off. Disconnect IFS switch. IFS switch is located in left front of trunk. Ensure IFS switch button is in the down (set) position. Measure resistance between IFS switch terminals. If resistance is less than 5 ohms, reconnect IFS switch. Check for open in power-to-fuel pump circuit, open in fuel pump or poor fuel pump ground. Repair wiring as necessary. Repeat QUICK TEST. If resistance is 5 ohms or more, attempt to reset IFS switch or replace IFS switch. Reconnect all components. Repeat QUICK TEST.

135) Code 524, 543 & Continuous Memory Code 583  KOEO Code 524 or 543 indicates that when PCM commanded fuel pump on, voltage was not detected on Fuel Pump Monitor (FPM) circuit (PCM terminal No. 8). Code 524 refers to low speed output (VCRM terminal No. 24; Pink/Black wire). Code 543 refers to high speed output. It is not possible to distinguish between circuits due to vehicle wiring and fuel pump operating strategy. Continuous Memory Code 583 indicates that when fuel pump was activated, power-to-fuel pump exceeded normal current draw. This could be due to a hard fault or an intermittent condition. Following are possible causes for these faults. Without Continuous Memory Code 583

• Open in power-to-fuel pump circuit between VCRM and FPM splice.
• Open in B (+) supply to VCRM (terminals No. 4 And 5).
• Short to power in left HO2S.

With Continuous Memory Code 583

• Short to ground in power-to-fuel pump/FPM circuit.

If Continuous Memory Code 583 is present, go to next step. If Continuous Memory Code 583 is not present, go to step 144).

136) Attempt To Re-Generate Continuous Memory Code 583  Turn ignition off. Clear the continuous memory. Refer to CLEARING CODES  under SELF-DIAGNOSTIC SYSTEM. Start engine. If engine will not start, crank engine for 5 seconds. Repeat KOEO SELF-TEST. If Continuous Memory Code 583 is present, code is a hard fault. Go to step 139). If Continuous Memory Code 583 is not present, code is intermittent. Go to next step.

137) Was KOEO Code 524 Or 543 Present In Step 136)  If KOEO Code 524 and/or 543 was present in step 136), an over-current condition (short to ground) was present sometime during last 80 warm-up cycles. Go to step 144). If KOEO Code 524 and/or 543 was not present in step 136), go to step 147).

139) Attempt To Isolate Short To Ground  Turn ignition off. Clear continuous memory. Disconnect Inertia Fuel Shutoff (IFS) switch. IFS switch is located in left front of trunk. Crank engine for 5 seconds. Repeat KOEO SELF-TEST. If Continuous Memory Code 583 is present (disregard other codes), go to step 140). If Continuous Memory Code 583 is not present, check for short to ground in power-to-fuel pump circuit or fuel pump. Repair wiring or replace fuel pump as necessary. After repair is complete, repeat QUICK TEST  .

140) Check For Short To Ground In Power-To-Fuel Pump/FPM Circuit  Turn ignition off. Ensure IFS switch is disconnected. Disconnect and inspect PCM and VCRM connectors. Clean or repair connectors as necessary. Install breakout box. Leave PCM and VCRM disconnected. Measure resistance between test pins No. 8 and 40 at breakout box. If resistance is more than 10,000 ohms, go to next step. If resistance is 10,000 ohms or less, repair short to ground in power-to-fuel pump/FPM circuit. Remove breakout box, and reconnect all components. Clear continuous memory. Start engine and wait 5 seconds. Turn ignition off. Repeat QUICK TEST.

141) Check VCRM  Turn ignition off. Ensure IFS switch is disconnected. Install breakout box. Leave PCM disconnected. Reconnect VCRM connector. Connect a jumper wire between test pins No. 22 and 40 at breakout box. Turn ignition on. Measure voltage between test pins No. 8 and 60 at breakout box. If voltage is more than 8.5 volts, replace PCM. Remove breakout box, and reconnect all components. Clear continuous memory. Start engine and wait 5 seconds. Turn ignition off. Repeat QUICK TEST. If voltage is 8.5 volts or less, replace VCRM. Remove breakout box, and reconnect all components. Clear continuous memory. Start engine and wait 5 seconds. Turn ignition off. Repeat QUICK TEST.

144) Check If Engine Starts With High Speed Fuel Pump (HFP) Relay Disconnected  Turn ignition off. Disconnect HFP relay. Relay is located in engine compartment fuse block. Attempt to start engine. If engine does not start or starts but runs for less than one minute, go to next step. If engine starts and runs for one minute, reconnect HFP relay. Go to step 127).

145) Check for B (+) To VCRM  Turn ignition off. Ensure HFP relay is disconnected. Disconnect and inspect VCRM connector. Clean or repair connector as necessary. Connect negative lead of DVOM to negative battery post. Using positive lead of DVOM, measure voltage at terminals No. 4 (Yellow wire) and No. 5 (Yellow wire) at VCRM connector. If both voltage readings are more than 10.5 volts, go to next step. If any reading is 10.5 volts or less, repair open in B (+) supply to VCRM. Ensure all related fuses are okay. Reconnect all components. Repeat QUICK TEST  .

146) Check Power-To-Fuel Pump Circuit Continuity  Turn ignition off. Disconnect HFP relay and VCRM. Measure resistance between terminal No. 24 (Pink/Black wire) and power-to-fuel pump terminal at HFP relay. See Fig 1 . If resistance is less than 10 ohms, replace VCRM. Reconnect all components. Repeat QUICK TEST. If resistance is 10 ohms or more, repair open in power-to-fuel pump circuit between VCRM and Fuel Pump Monitor (FPM) splice. Reconnect all components. Repeat QUICK TEST.

147) Check For Intermittent Short To Ground In Power-To-Fuel Pump Circuit  Turn ignition off. Visually inspect power-to-fuel pump circuit between VCRM and fuel pump. Also, inspect Fuel Pump Monitor (FPM) circuit to PCM and power-to-fuel pump circuit at High Speed Fuel Pump (HFP) relay. Repair wiring as necessary. Install a fuel gauge or listen to fuel pump to check if fuel pump quits while performing wiggle test.

Start engine. Shake, wiggle and bend Pink/Black wire (power-to-fuel pump circuit) between VCRM, fuel pump, PCM and HFP relay. To simulate road shock, lightly tap on Inertia Fuel Shutoff (IFS) switch, fuel pump, HFP relay, VCRM and fuel pump. If fuel pump stops, fuel pressure drops or engine stalls or stumbles, a short to ground in power-to-fuel pump circuit has been detected. Isolate fault and repair as necessary. Clear continuous memory (Code 583 should have been set). Start engine and wait 5 seconds. Turn ignition off. Repeat QUICK TEST. If no fault is detected, go to next step.

148) Again, Check For Intermittent Short To Ground In Power-To-Fuel Pump  Turn ignition off. Disconnect PCM, VCRM and fuel pump. Inspect connectors. Clean or repair connectors as necessary. Install breakout box. Leave PCM, VCRM and fuel pump disconnected. Connect a test light between test pins No. 1 (KAPWR) and No. 8 (FPM) at breakout box. Observe test light, and shake, wiggle and bend Pink/Black wire (power-to-fuel pump circuit) between VCRM, fuel pump, PCM and HFP relay. To simulate road shock, lightly tap on Inertia Fuel Shutoff (IFS) switch, fuel pump, HFP relay and VCRM. If a fault is detected, test light will turn on, indicating a short to ground. If a short to ground is detected, isolate fault and repair wiring as necessary. Start engine and wait 5 seconds. Turn ignition off. Repeat QUICK TEST. If a short to ground is not detected, fault is intermittent and cannot be duplicated at this time. Testing is complete. Reconnect all components. For further diagnosis, proceed to the appropriate TESTS W/O CODES - EEC-IV (1.9L) article in this section.

150) Continuous Memory Code 524, 543 Or 556  Continuous Memory Code 524 or 543 indicates that when PCM commanded fuel pump on, voltage was not detected at the power-to-fuel pump circuit. Code 524 refers to low speed output (VCRM terminal No. 24; Pink/Black wire). Code 543 refers to high speed output. It is not possible to distinguish between circuits due to vehicle wiring and fuel pump operating strategy. Following are possible causes for these faults.

• Open in power-to-fuel pump circuit between VCRM and FPM splice.
• Open in B (+) supply to VCRM (terminals No. 4 And 5).
• Left HO2S short to power.

Continuous Memory Code 556 indicates that sometime during vehicle operation, fuel pump primary circuit failure occurred. Possible cause for this fault is an open or short in fuel pump circuit (PCM terminal No. 22). If Continuous Memory Code 583 is also present, go to step 136). If Continuous Memory Code 583 is not present, go to next step.

151) Check Power-To-Fuel Pump & Fuel Pump Circuits  Start engine. Disconnect High Speed Fuel Pump (HFP) relay. Relay is located in engine compartment fuse block. Connect a test light between ground and power-to-fuel pump terminal at HFP relay connector. If a fault is detected, test light will go out, indicating a open FP circuit. Also, listen for engine stall/stumble or fuel pump turning off. Observe test light and perform the following:

• For Code 524 or 543, shake, wiggle and bend Pink/Black wire (power-to-fuel pump circuit) between terminal No. 24 at VCRM and Fuel Pump Monitor (FPM) splice. Also shake, wiggle and bend Yellow wire (B (+) circuit) between terminals No. 4 and 5 at VCRM.
• For Code 556, shake, wiggle and bend Light Blue/Orange wire (fuel pump circuit) between terminals No. 22 at PCM and No. 18 at VCRM.

If a short to ground is detected, isolate fault and repair wiring as necessary. Clear continuous memory. Repeat QUICK TEST  . If Code 556 is present and a short to ground is not detected, go to next step. If Code 556 is not present and a short to ground is not detected, go to step 158).

152) Check For Intermittent Short To Ground In Fuel Pump Ckt.  Turn ignition off. Disconnect and inspect PCM and VCRM connectors. Clean or repair connectors as necessary. Connect ohmmeter between terminals No. 18 (Light Blue/Orange wire) and No. 1 (Black wire) at VCRM connector. Observe ohmmeter, and shake, wiggle and bend Light Blue/Orange wire (fuel pump circuit) between VCRM and PCM connectors. Also check fuel pump circuit to Data Link Connector (DLC). If a fault is detected, ohmmeter will show continuity, indicating a short to ground. If continuity exists, isolate fault and repair wiring as necessary. Clear continuous memory. Repeat QUICK TEST. If no continuity exists, fault is intermittent and cannot be duplicated at this time. Testing is complete. Reconnect all components. For further diagnosis, see TESTS W/O CODES - EEC-IV (1.9L) article in this section.

155) Continuous Memory Code 542  Continuous Memory Code 542 indicates that one of the following conditions has occurred.

• Fuel pump circuit activated when PCM expected circuit to be off.
• Open in fuel pump monitor (FPM) circuit, power to fuel pump, fuel pump or fuel pump ground circuit.
• Short to power in FPM or power-to-fuel pump circuits.
• VCRM output driver or high speed fuel pump (HFP) relay contacts stuck closed.
• Short to ground in HFP circuit.
• Short to power in left HO2S signal circuit.
• Engine stall due to excessive load.

Start engine. Check for engine stall/stumble while performing the following (if possible, listen for fuel pump turning off). Shake, wiggle and bend Pink/Black wire (power-to-fuel pump circuit) between fuel pump and FPM splice. To simulate road shock, lightly tap on fuel pump, Inertia Fuel Shutoff (IFS) switch and VCRM. If engine stalls or stumbles, isolate fault and repair wiring as necessary. Clear continuous memory. Repeat QUICK TEST. If engine does not stall or stumble, go to next step.

156) Check For Intermittent Open Or Short In FPM, Power-To-Fuel Pump & Fuel Pump Ground Circuits  Turn ignition off. Disconnect and inspect PCM connector. Clean or repair connector as necessary. Install breakout box. Leave PCM disconnected. Connect a test light between test pins No. 8 and 37 at breakout box. Turn ignition on, engine off. Observe test light, and shake, wiggle and bend the following circuits.

• Fuel pump monitor (FPM) circuit.
• Power-to-fuel pump circuit.
• Fuel pump ground and HFP relay circuits between HFP relay and VCRM.

To simulate road shock, lightly tap on Inertia Fuel Shutoff (IFS) switch, VCRM and HFP relay. If a fault is detected, test light will turn off indicating an open circuit. Test light will also turn off and fuel pump will run, if a short to power or HFP circuit short to ground is detected. If a fault is detected, isolate fault and repair wiring as necessary. Remove breakout box. Reconnect all components. Repeat QUICK TEST  . If a fault is not detected, proceed to step 158).