Engine Controls - System/component Tests: Other Dodge Neon I

ENGINE COOLANT TEMPERATURE SENSOR

Turn ignition off. Disconnect Engine Coolant Temperature (ECT) sensor connector. For ECT sensor location, see ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION table. Using a DVOM, measure resistance between ECT sensor terminals. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE table.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION (1)

ENGINE COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE

HEATED OXYGEN SENSOR (HO2S)

1. Turn ignition off. Disconnect left/right or upstream/downstream Heated Oxygen Sensor (HO2S) connector. Using a DVOM, check resistance between HO2S connector 2 White wires on sensor side of connector. If resistance is 4-7 ohms, go to next step. If resistance is not 4-7 ohms, replace defective HO2S.
2. Only HO2S heater circuit is tested. If HO2S is still suspected of malfunctioning, see the «TESTS W/CODES»(ref-11307) article.

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR

1. Turn ignition on with engine off. DO NOT disconnect Manifold Absolute Pressure (MAP) sensor connector. Using a DVOM, check voltage between MAP sensor connector terminals No. 1 and 4. (Scheme 55) Voltage should be 4-5 volts. If voltage is 4-5 volts, go to next step. If voltage is not 4-5 volts, see «TESTS W/CODES»(ref-11307) article.
2. Start engine and run until normal operating temperature is reached. Using a DVOM, check voltage between MAP sensor connector terminals No. 1 and 4. (Scheme 55) With engine idling, voltage should be 1.5-2.1 volts. If voltage is within specification, MAP sensor is functioning properly. If voltage is not within specification, see the «TESTS W/CODES»(ref-11307) article.

Scheme 55

THROTTLE POSITION (TP) SENSOR

1. Turn ignition on. DO NOT disconnect Throttle Position (TP) sensor connector. Using a DVOM, measure voltage on center terminal of TP sensor connector. Voltage should be .38-1.03 volts. If voltage is within specification, go to next step. If voltage is not within specification, see «TESTS W/CODES»(ref-11307) article.
2. While observing DVOM, slowly open throttle to Wide Open Throttle (WOT). Voltage should smoothly increase as throttle is opened. At WOT, voltage should be 3.1-4.0 volts. If voltage does not change smoothly or is not within specification at WOT, see the «TESTS W/CODES»(ref-11307) article. If voltage changes smoothly and is within specification at WOT, TP sensor is functioning properly.

AUTO SHUTDOWN (ASD) & FUEL PUMP RELAYS

Note. Auto Shutdown (ASD) and fuel pump relays are tested using the same procedures.

1. Turn ignition off. Remove Auto Shutdown (ASD) relay or fuel pump relay. Using a DVOM, measure resistance between relay terminals No. 85 and 86. (Scheme 56) Resistance should be 70-80 ohms. If resistance is within specification, go to next step. If resistance is not within specification, replace relay.
2. Using a DVOM, check for continuity between relay terminals No. 30 and 87A. (Scheme 56) Continuity should be present. If continuity is present, go to next step. If continuity is not present, replace relay.
3. Using a DVOM, check for continuity between relay terminals No. 30 and 87. (Scheme 56) Continuity should not be present. If continuity is not present, go to next step. If continuity is present, replace relay.
4. Using a jumper wire, ground relay terminal No. 85. (Scheme 56) Using another jumper wire, apply battery voltage to relay terminal No. 86. Relay should activate. When relay activates, DVOM should display infinity between relay terminals No. 30 and 87A. If relay activated and DVOM displayed infinity, relay is functioning properly. If relay did not activate or DVOM did not display infinity, replace relay.

Scheme 56

INJECTORS

Turn ignition off. Disconnect injector electrical connector. Using a DVOM, measure resistance across injector terminals. See the INJECTOR RESISTANCE table. If resistance is within specification, injector coils are okay. If resistance is not within specification, replace injector.

INJECTOR RESISTANCE

IGNITION SYSTEM

Note. For basic ignition checks, see BASIC TESTING article.

EXHAUST GAS RECIRCULATION (EGR) SYSTEM

1. Inspect hose connections between intake manifold, EGR solenoid and transducer, and EGR valve. Replace hardened, cracked and damaged hoses.
2. Ensure engine coolant temperature is more than 150°F (66°C). Put transmission in Neutral. Allow engine to idle for approximately 70 seconds. Suddenly accelerate engine to approximately 2000 RPM, but not more than 3000 RPM. EGR valve stem should move when accelerating engine. Repeat test several times to confirm EGR valve stem movement. If EGR valve stem moves, EGR control system if functioning properly, go to next step. If EGR valve stem does not move see scheme 5: EGR DIAGNOSTIC CHART.
3. Remove vacuum hose from EGR valve. Connect a hand-held vacuum pump to EGR valve. With engine idling at operating temperature, slowly apply vacuum to EGR valve. When vacuum reaches 2.0-3.5 in. Hg, engine idle will become rough or engine may stall. If engine idle does not become rough or engine does not stall, go to next step. If engine idle becomes rough or engine stalls, EGR system is functioning properly.
4. Remove EGR valve and EGR tube. Inspect EGR valve and EGR tube for plugged passages. Also check intake manifold inlet passage. Repair or replace components as necessary. If necessary to replace EGR valve or EGR solenoid/transducer assembly, EGR valve and EGR solenoid/transducer assembly must be replaced together because they are calibrated to match each other.

PCV Valve

Disconnect hose from PCV valve. Remove PCV valve from valve cover. Reconnect hose to PCV valve. Start engine and let idle. Put finger over opening of PCV valve. Ensure a vacuum is felt with finger. If vacuum is not felt, clean or replace PCV valve as necessary.