Engine Control System - Trouble Shooting - No Codes: Other

Preliminary Checks

Symptom checks cannot be used properly unless problem occurs while vehicle is being tested. To reduce diagnostic time, ensure steps in BASIC DIAGNOSTIC PROCEDURES - 1.8L VIBE article and SELF-DIAGNOSTICS - 1.8L VIBE article were performed before diagnosing a symptom. The following symptoms are available for diagnosis

«Hard Start»(ref-153013-S26334488242003031100000)
«Surges/Chuggles»(ref-153013-S30828385492003031100000)
«Lack Of Power, Sluggishness Or Sponginess»(ref-153013-S05959300002003031100000)
«Detonation/Spark Knock»(ref-153013-S26273359952003031100000)
«Hesitation, Sag, Stumble»(ref-153013-S10829696742003031100000)
«Cuts Out, Misses»(ref-153013-S07106215882003031100000)
«Poor Fuel Economy»(ref-153013-S08891832092003031100000)
«Poor Fuel Fill Quality»(ref-153013-S41128751862003031100000)
«Rough, Unstable, Or Incorrect Idle & Stalling»(ref-153013-S30729456532003031100000)
«Dieseling, Run-On»(ref-153013-S31106892612003031100000)
«Backfire»(ref-153013-S09688025742003031100000)
«Restricted Exhaust»(ref-153013-S35489441112003031100000)
Engine Cranks But Does Not Run. See «ENGINE CRANKS BUT DOES NOT RUN»(ref-152426-S24080731382003032400000) under NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - 1.8L VIBE article.
Malfunction Indicator Light Inoperative. Go to «MIL INOPERATIVE»(ref-152429-S36408550102003020400000) under SYSTEM TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
Malfunction Indicator Light Always On. Go to «MIL ALWAYS ON»(ref-152429-S05423133762003020400000) under SYSTEM TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.

Intermittent

Test the vehicle under the same conditions that the customer reported in order to verify the system is operating as designed.

EXHAUST LEAKAGE

WARNING

To avoid being burned, do not service the exhaust system while it is still hot. Service the system when it is cool.

HARD START

Note. For circuit reference, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. For component locations, see COMPONENT LOCATIONS in SELF-DIAGNOSTICS - 1.8L VIBE article. For connector identification, see CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 1.8L VIBE article.

Definition

Engine cranks OK, but does not start for a long time. Engine does eventually run, or may start but immediately dies.

See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-152429-S10298708072003020400000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 1.8L VIBE article.
Ensure the driver is using the correct starting procedure.

Sensor Checks

Check the Engine Coolant Temperature (ECT) sensor using a scan tool to compare the engine coolant temperature with the ambient air temperature on a cold engine. If coolant temperature reading is more than 9°F (5°C) more or less than the ambient air temperature on a cold engine, check for high resistance in the coolant sensor circuit or in the sensor. See «TEMPERATURE VS. RESISTANCE»(ref-153013-S18916190452003031100000) table. TEMPERATURE VS. RESISTANCE °F °C Resistance - Ohms 176 80 315 158 70 435 140 60 480 122 50 810 113 45 940 104 40 1150 95 35 1360 86 30 1600 77 25 2000 68 20 2400 59 15 3000 50 10 3600 41 5 4600 32 0 5700 23 -5 7400 14 -10 9800 5 -15 12700 -4 -20 16000
Check the Throttle Position (TP) sensor. A sticking throttle shaft or a binding throttle linkage will causes a high TP sensor voltage. Under these conditions, PCM may not control the idle. Monitor the TP sensor angle with the scan tool. The indicated angle should be approximately 9-11 percent with throttle closed.
Inspect the Mass Air Flow (MAF) sensor operation. Run engine to normal operating temperature. Turn OFF all accessories and observe the MAF sensor at idle with a scan tool. If the MAF sensor reading is more than 3.5 g/s, see «DTC P0101: MAF SENSOR PERFORMANCE»(ref-152429-S06808177572003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
Check the Crankshaft Position (CKP) sensor engine reference signal with a scan tool. Observe ENGINE SPEED parameter while cranking the engine. The scan tool should indicate a steady 200-300 RPM while cranking. If erratic values, such as sudden spikes in the engine speed are displayed, the engine reference signal is not stable enough for the engine to start and run properly.

Fuel System Checks

Check the fuel pump relay for correct operation. Observe the fuel pump relay operation on a scan tool while cranking the engine.
Check the fuel pressure. See «FUEL SYSTEMS»(ref-152779-S16928737762003022500000) in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check for water contamination in the fuel. See «ALCOHOL/CONTAMINANTS-IN-FUEL DIAGNOSIS»(ref-152779-S09199734132003022500000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check for no Crank Signal at the Powertrain Control Module (PCM) harness connector C2 terminal No. 9 (Black wire) if the vehicle takes longer to start in cold weather. Observe the STARTER SWITCH parameter on a scan tool while cranking the engine. The PCM provides slightly more fuel for engine start up when receiving the crank input.
Check the fuel pump check valve. A faulty fuel pump check valve will allow the fuel in the lines to drain back into the tank after stopping the engine. This condition is especially troublesome on hot soak restarts. To check for this condition perform the following steps: Turn ignition switch to OFF position. Install a fuel pressure gauge. See «FUEL GAUGE»(ref-153233-S05610451762003032700000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 1.8L VIBE article. Pressurize fuel rail by turning the ignition switch ON and OFF a few times. Turn ignition switch to RUN position and observe fuel pressure. The fuel pressure has to remain more than 24 psi (147 kPa).

Ignition System Checks

Check ignition system secondary output using Spark Tester (J 26792), or equivalent. See «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(ref-152779-S07851640532003022500000) under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Inspect spark plugs for correct operation and good ignition system performance.
Check for bare or shorted ignition system wiring.
Check for loose ignition coil connections.

Additional Checks

An Idle Air Control (IAC) system that is malfunctioning can cause a hard start condition. Hold throttle open slightly while starting the engine. After vehicle is started, the scan tool can be used to check the IAC valve operation. Operate the IAC valve using the scan tool while checking for a smooth increase and decrease in engine speed. If engine speed can be controlled, IAC system is functioning normally. If engine speed cannot be controlled using the scan tool, refer to DIAGNOSTIC AIDS under «DTC P0505: IDLE CONTROL SYSTEM»(ref-152429-S07525211862003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
If the engine stalls after starting, check for a fault in the CMP Actuator System or the Rocker Arm Oil Control System. A stuck On control solenoid can cause the engine to stall at idle speeds. See «DTC P1346: INTAKE CMP SYSTEM PERFORMANCE»(ref-152429-S35049561932003020400000) and «DTC P1692: ROCKER ARM ACTUATOR SYSTEM STUCK ON»(ref-152429-S30896303472003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
Check Technical Service Bulletins for any updates.

SURGES/CHUGGLES

The engine has a power variation under a steady throttle or cruise. There is a feeling as if the vehicle speeds up and slows down with no change in the accelerator pedal.

See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-152429-S10298708072003020400000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 1.8L VIBE article.
Ensure the driver understands the A/C compressor operation.
Use a scan tool to ensure the reading of the Vehicle Speed Sensor (VSS) matches the reading of the instrument panel speedometer. Transmission performance can be affected by incorrect VSS readings. If accuracy of the VSS is a concern, see SPEEDOMETER &/OR ODOMETER INACCURATE OR INOPERATIVE in appropriate INSTRUMENT PANEL article in ACCESSORIES & EQUIPMENT.

Check Heated Oxygen Sensor (HO2S) 1 performance. See DIAGNOSTIC AIDS for «DTC P0130: HO2S 1 CIRCUIT»(ref-152429-S33505930392003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
Inspect the Mass Air Flow (MAF) sensor operation. Run engine to normal operating temperature. Turn OFF all accessories and observe the MAF sensor at idle using a scan tool. If MAF sensor reading is more than 3.5 g/s, see «DTC P0101: MAF SENSOR PERFORMANCE»(ref-152429-S06808177572003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
Check for correct operation of the Engine Coolant Temperature (ECT) sensor. A fixed or inaccurate ECT sensor reading can cause the engine to surge, especially at low speeds and at stops.

Determine if a rich or lean system can cause the condition. Drive the vehicle at the speed of the complaint. Monitoring the Fuel Trim may help identify the problem. Lean The Long Term Fuel Trim will be more than 20 percent. Rich The Long Term Fuel Trim will be less than -20 percent.
Check the fuel injectors. Perform the following procedures: Fuel Injector Coil Test. See «FUEL INJECTOR COIL TEST - ENGINE COOLANT TEMPERATURE BETWEEN 50-95°F (10-35°C)»(ref-152779-S06830036892003022500000) or «FUEL INJECTOR COIL TEST - ENGINE COOLANT TEMPERATURE OUTSIDE 50-95°F (10-35°C)»(ref-152779-S00127225072003031100000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article. Fuel Injector Balance Test. See «FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL»(ref-152779-S08897027942003022500000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check the fuel pressure while the condition exists. See «FUEL SYSTEM DIAGNOSIS»(ref-152779-S03797432242003031100000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.

Check ignition system secondary output using Spark Tester (J 26792), or equivalent. See «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(ref-152779-S07851640532003022500000) under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Inspect the spark plugs for correct operation and good ignition system performance.

Check Powertrain Control Module (PCM) grounds for proper location and clean, tight connections.
Inspect Positive Crankcase Ventilation (PCV) valve for correct operation and correct part. See «POSITIVE CRANKCASE VENTILATION»(ref-152779-S00418169322003022500000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check the generator for the correct output voltage. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS.
Check the vacuum lines and hoses for leaks or incorrect routing
If equipped with an automatic transmission, inspect for correct operation and correct shifting of transmission. Inspect for correct operation and engagement of the Torque Converter Clutch (TCC). See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.

LACK OF POWER, SLUGGISHNESS OR SPONGINESS

The engine delivers less than expected power. There is little or no increase in speed when partially applying the accelerator pedal.

See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-152429-S10298708072003020400000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 1.8L VIBE article.
Compare the customers vehicle with a similar unit in order to determine if the customer has an actual problem.
Remove the air filter element and check for dirt or restrictions.
Check the air inlet duct for any blockage or restrictions.
Check the transmission shift pattern and down-shift operation.

Sensor/System

Check Mass Air Flow (MAF) sensor operation. Run engine to normal operating temperature. Turn OFF all accessories and observe MAF sensor at idle with a scan tool. If the MAF sensor reading is more than 3.5 g/s, see DTC P0101: MAF SENSOR PERFORMANCE under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.

Check for a restricted fuel filter or incorrect fuel pressure.
Check the fuel injectors. Perform the following procedures: Fuel Injector Coil Test. See «FUEL INJECTOR COIL TEST - ENGINE COOLANT TEMPERATURE BETWEEN 50-95°F (10-35°C)»(ref-152779-S06830036892003022500000) or «FUEL INJECTOR COIL TEST - ENGINE COOLANT TEMPERATURE OUTSIDE 50-95°F (10-35°C)»(ref-152779-S00127225072003031100000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article. Fuel Injector Balance Test. See «FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL»(ref-152779-S08897027942003022500000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check for contaminated fuel.

Check ignition system secondary output using Spark Tester (J 26792), or equivalent. See «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(ref-152779-S07851640532003022500000) under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Inspect the spark plugs for correct operation and good ignition system performance.
Check Knock Sensor (KS) and sensor circuit shielding. A faulty knock sensor or signal interference could cause excessive retard of the ignition timing advance. Observe the spark parameter on a scan tool and compare with a known good vehicle. A typical value at 60 MPH (98 km/h) with all engine accessories off is 26-32 degrees.

Exhaust System Checks

Check the exhaust system for a possible restriction.
Inspect the exhaust system for damaged or collapsed pipes. Inspect the muffler for heat distress or a possible internal failure.

Engine Mechanical Check

Check for any of the following engine mechanical problems: A low compression An incorrect valve timing An incorrect or worn camshaft
See appropriate article in ENGINES.

If the loss of power is above 6000 RPM, check Rocker Arm Oil Control system for the correct operation. See «DTC P1693: ROCKER ARM ACTUATOR SYSTEM STUCK OFF»(ref-152429-S17792982272003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
Check the Powertrain Control Module (PCM) grounds for proper locations and clean, tight connections.
Check the generator output voltage. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS.

DETONATION/SPARK KNOCK

A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening.

See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-152429-S10298708072003020400000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 1.8L VIBE article.
Road test the vehicle and determine the severity of the complaint.

Cooling System Checks

Check for any obvious overheating problems.
Check for a low engine coolant level.
Check for a loose water pump belt.
Check for restricted air flow through the radiator, or a restricted coolant flow.
Check for a faulty or incorrect thermostat.
Check for a correct coolant solution. The solution should be a 50/50 mix of anti-freeze and water.

Sensor Check

Check for an Engine Coolant Temperature (ECT) sensor that has a shifted value. See TEMPERATURE VS. RESISTANCE table.

Check to determine if a lean system causes the condition. Drive vehicle at the speed of the complaint. Monitoring the Fuel Trim will help identify the problem. If the system is lean, the Long Term Fuel Trim will be more than 20 percent.
Check the fuel pressure. See «FUEL SYSTEM DIAGNOSIS»(ref-152779-S03797432242003031100000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check fuel injectors. Perform Fuel Injector Coil Test procedure and the Fuel Injector Balance Test procedure. See «FUEL INJECTOR COIL TEST - ENGINE COOLANT TEMPERATURE BETWEEN 50-95°F (10-35°C)»(ref-152779-S06830036892003022500000) and «FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL»(ref-152779-S08897027942003022500000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check for inferior quality fuel and the proper octane rating. See «ALCOHOL/CONTAMINANTS-IN-FUEL DIAGNOSIS»(ref-152779-S09199734132003022500000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article. Fill fuel tank with a known high quality fuel that meets the vehicles minimum octane requirements. Road test vehicle and re-evaluate vehicle performance.

Check the spark plugs for the correct gap.
Inspect the spark plugs for excessive deposits that can glow and pre-ignite the air/fuel mixture.
Check the spark plugs for the correct type and the correct heat range.

Check the exhaust system for a possible restriction.
Inspect the exhaust system for damaged or collapsed pipes. Inspect the muffler for heat distress or a possible internal failure.

Check for carbon buildup. Remove the carbon with a top engine cleaner product. Follow the manufacturer instructions on the container.
Check for excessive oil entering the combustion chamber. See appropriate article in ENGINES.
Check for incorrect basic engine parts such as the cam, the heads, the pistons, etc.

Check for a dirty air filter or a restriction in the air induction system.
Check for any Service Bulletins or updates.

HESITATION, SAG, STUMBLE

The vehicle has a momentary lack of response when pushing down on the accelerator. The condition can occur at any vehicle speed. The condition is usually most severe when trying to make the vehicle move, as from a stop sign. The condition may cause the engine to stall if severe enough.

Preliminary Check

See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-152429-S10298708072003020400000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 1.8L VIBE article.

Check for a restricted fuel filter or incorrect fuel pressure. See «FUEL SYSTEM DIAGNOSIS»(ref-152779-S03797432242003031100000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check the fuel injectors. Perform the following procedures: Fuel Injector Coil Test. See «FUEL INJECTOR COIL TEST - ENGINE COOLANT TEMPERATURE BETWEEN 50-95°F (10-35°C)»(ref-152779-S06830036892003022500000) or «FUEL INJECTOR COIL TEST - ENGINE COOLANT TEMPERATURE OUTSIDE 50-95°F (10-35°C)»(ref-152779-S00127225072003031100000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article. Fuel Injector Balance Test. See «FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL»(ref-152779-S08897027942003022500000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check for water contamination of the fuel.
Check the Throttle Position (TP) sensor for binding or sticking. Voltage should increase at a steady rate as the throttle moves toward Wide Open Throttle (WOT).
Inspect the operation of the Mass Air Flow (MAF) sensor. Run the engine to normal operating temperature. Turn OFF all accessories and observe the MAF sensor at idle with a scan tool. If the MAF sensor reading is more than 3.5 g/s, see «DTC P0101: MAF SENSOR PERFORMANCE»(ref-152429-S06808177572003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
Check the Evaporative Emission (EVAP) control system. See «EVAPORATIVE EMISSION CONTROL SYSTEM DIAGNOSIS»(ref-152779-S17488005022003022500000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.

Inspect the spark plugs for correct operation and good ignition system performance.

Check the Service Bulletins for any updates.
Check the generator output voltage. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS.

CUTS OUT, MISSES

A steady pulsation or jerking that follows engine speed, usually more pronounced as the engine load increases. The exhaust has a steady spitting sound at idle, low speed or on hard acceleration.

See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-152429-S10298708072003020400000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 1.8L VIBE article.

Check the Engine Coolant Temperature (ECT) sensor using a scan tool to compare the engine coolant temperature with the ambient air temperature on a cold engine. If the coolant temperature reading is more than 9°F (5°C) more or less than the ambient air temperature on a cold engine, check for a high resistance in the coolant sensor circuit or in the sensor. See «TEMPERATURE VS. RESISTANCE»(ref-153013-S18916190452003031100000) table.
Inspect the Mass Air Flow (MAF) sensor operation. Run engine to normal operating temperature. Turn OFF all accessories and observe the MAF sensor at idle with a scan tool. If the MAF sensor reading is more than 3.5 g/s, see «DTC P0101: MAF SENSOR PERFORMANCE»(ref-152429-S06808177572003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.

Check for a restricted fuel filter or an incorrect fuel pressure. See «FUEL SYSTEM DIAGNOSIS»(ref-152779-S03797432242003031100000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check the fuel injectors. Perform the Fuel Injector Coil Test procedure and the Fuel Injector Balance Test procedure. See «FUEL INJECTOR COIL TEST - ENGINE COOLANT TEMPERATURE BETWEEN 50-95°F (10-35°C)»(ref-152779-S06830036892003022500000) and «FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL»(ref-152779-S08897027942003022500000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check for water contamination of the fuel.

Check for an ignition system misfire.

CAUTION

Do not perform this test for more than 2 minutes in order to prevent damage to the catalytic converter.

Start the engine.
Remove one ignition coil at a time using insulated pliers.
If there is an RPM drop on all cylinders (equal to within 50 RPM), see «ROUGH, UNSTABLE, OR INCORRECT IDLE AND STALLING»(ref-153013-S30729456532003031100000) .
Check for spark on the suspected cylinders with Spark Tester (J 26792), or equivalent, if there is no RPM drop on one or more cylinders.
If there is no spark, see «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(ref-152779-S07851640532003022500000) under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING article.
If there is spark, inspect the spark plugs for correct operation and good ignition system performance.

Check the ignition system for moisture, dust, cracks, burns, etc.

POOR FUEL ECONOMY

Fuel economy, as measured by an actual road test, is noticeably lower than expected. Also, the economy is noticeably lower than it was on this vehicle at one time, as previously shown by an actual road test.

See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-152429-S10298708072003020400000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 1.8L VIBE article.
Check air cleaner element for dirt or restrictions.
Visually and physically check vacuum hoses for splits, kinks, and proper connections as shown on the Vehicle Emission Control Information label.
Check the owners driving habits for any of the following: A/C system defroster mode is ON all the time. The tires are improperly inflated. Heavy loads are frequently being carried. Heavy acceleration and high speeds are common. Frequent short trips. Prolonged periods of idling. Driving on unpaved or rough roads.
Suggest that the owner refill the fuel tank and recheck the fuel economy.

Check the type, quality, and alcohol content of the fuel. Oxygenated fuels have lower energy and may deliver reduced fuel economy. See «FUEL SYSTEM SPECIFICATIONS»(ref-152779-S26034240542003031200000) and «ALCOHOL/CONTAMINANTS-IN-FUEL DIAGNOSIS»(ref-152779-S09199734132003022500000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check for the correct fuel pressure. See «FUEL SYSTEM DIAGNOSIS»(ref-152779-S03797432242003031100000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.

Inspect the spark plugs for correct operation and good ignition system performance.
Check the ignition coil boots for cracking, chafing, and loose connections.
Observe the SPARK parameter on the scan tool at idle, while operating rear defogger, A/C system, or headlights. If scan tool display remains fixed at 10 degrees, check for a short to ground in the Diagnostic Request circuit from the Powertrain Control Module (PCM) connector C4 terminal No. 20 to the Data Link Connector (DLC).
Check the Knock Sensor (KS) and sensor circuit shielding. A faulty knock sensor or signal interference could cause excessive retard of the ignition timing advance. Observe the SPARK parameter on a scan tool and compare with a known good vehicle. A typical value at 60 MPH (98 km/h) with all engine accessories off is 26-32 degrees.

Check for the correct engine coolant level.
Check the engine thermostat for always being open or for the wrong heat range.

Check the clutch adjustment in vehicles equipped with a manual transmission. See appropriate FWD article in CLUTCHES.
Check the transmission shift pattern and the Torque Converter Clutch (TCC) operation in vehicles equipped with an automatic transmission. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
Check for dragging brakes.
Check for uneven or premature tire wear. A suspension misalignment can cause reduced fuel economy. See SPECIFICATIONS & PROCEDURES - VIBE article under WHEEL ALIGNMENT in SUSPENSION.
Verify tires and wheels are similar to OEM. Wide performance tires create more drag and taller tires can cause odometer discrepancies.
Check for a low mileage engine. Fuel economy may not be near expected levels until the engine has had 3000-5000 miles (5000-8000 km) to break in.
Check for add-on equipment like luggage racks and carriers. Wind resistance can lower fuel economy.
Check for Technical Service Bulletins and for any updates or information.

POOR FUEL FILL QUALITY

Difficulty when refueling the vehicle.

Difficult To Fill

The fuel filler pipe check valve is stuck closed.
The Fill Limiter Vent Valve (FLVV) is stuck closed.
The Evaporative Emission (EVAP) canister drain hose is blocked or restricted.
The EVAP canister drain line check ball is stuck closed.
Any restricted vapor lines or hoses.
The EVAP canister is restricted.
A fuel with high Reid Vapor Pressure (RVP) characteristics.
A high fuel temperature.
The fuel filler hose/pipe is pinched, kinked, or blocked.

Over Fill

The pressure relief valve in the Fill Limiter Vent Valve (FLVV) is stuck open.
The pressure relief valve in the FLVV is leaking.
FLVV is stuck open.
FLVV is leaking.

Pre-Mature Shut-Off Of The Fuel Dispensing Nozzle

The Fill Limiter Vent Valve (FLVV) is stuck closed.
The Evaporative Emission (EVAP) canister drain hose is blocked or restricted.
The EVAP canister drain line check ball is stuck closed.
Any restricted vapor lines or hoses.
The EVAP canister is restricted.
A fuel with high Reid Vapor Pressure (RVP) characteristics.
A high fuel temperature.

Fuel Spitback

The fuel filler pipe check valve is stuck open.
The filler pipe check valve is stuck closed.
The filler pipe check valve is leaking.
A fuel with high Reid Vapor Pressure (RVP) characteristics.
A high fuel temperature.

Liquid Fuel In EVAP Canister

The fill limiter vent valve is stuck open.
The fill limiter vent valve is leaking.

Liquid Fuel Leak

The pressure relief valve in the Fill Limiter Vent Valve (FLVV) is stuck open.
The pressure relief valve in the FLVV is leaking.
The fuel filler hose is loose or torn.
The FLVV is stuck open.

Fuel Odor

The pressure relief valve in the Fuel Limiter Vent Valve (FLVV) is stuck open.
The pressure relief valve in the FLVV is leaking.
The EVAP canister is saturated with fuel.

ROUGH, UNSTABLE, OR INCORRECT IDLE & STALLING

The engine runs unevenly at idle. If severe enough, the engine or vehicle may shake. The engine idle speed may vary in RPM. Either condition may be severe enough to stall the engine. The engine idles at an incorrect speed.

See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-152429-S10298708072003020400000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 1.8L VIBE article.

Inspect the Heated Oxygen Sensors (HO2S) 1 and HO2S 2 for a condition that can affect sensor activity and response. See DIAGNOSTIC AIDS for the following DTCs under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article: «DTC P0130: HO2S 1 CIRCUIT»(ref-152429-S33505930392003020400000) «DTC P0133: HO2S 1 SLOW RESPONSE»(ref-152429-S19923693652003020400000) «DTC P0135 OR P0141: HO2S HEATER PERFORMANCE»(ref-152429-S07223572442003020400000) «DTC P0136: HO2S 2 CIRCUIT»(ref-152429-S38252420842003020400000)
Inspect the Throttle Position (TP) sensor. A sticking throttle shaft or a binding throttle linkage will causes a high TP sensor voltage. Under these conditions the Powertrain Control Module (PCM) may not control the idle. Monitor TP sensor angle with the scan tool. The indicated angle should be approximately 11 percent with throttle closed.
Inspect the Engine Coolant Temperature (ECT) sensor. A fixed or inaccurate ECT sensor reading can cause the engine idle to surge or race. Using the scan tool, compare ECT with the ambient air temperature on a cold engine. If the engine coolant is 9°F (5°C) more than or 9°F (5°C) less than the ambient air temperature, check resistance of the coolant sensor. See «TEMPERATURE VS. RESISTANCE»(ref-153013-S18916190452003031100000) table. If ECT is significantly less than the ambient air temperature, inspect coolant sensor electrical circuit for high resistance.
Inspect Mass Air Flow (MAF) sensor operation. Run engine to normal operating temperature. Turn OFF all accessories and observe MAF sensor at idle using scan tool. If MAF sensor reading is more than 3.5 g/s, see «DTC P0101: MAF SENSOR PERFORMANCE»(ref-152429-S06808177572003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article. If MAF sensor reading is less than 1.0 g/s, check for a vacuum leak between MAF sensor and engine.

Inspect the operation of the fuel system for rich or lean condition. Operate the vehicle under the conditions that caused the concern. Monitor the Fuel Trim parameter on a scan tool in order to identify the problem. Lean The Long Term Fuel Trim will be more than 20 percent. Refer to DIAGNOSTIC AIDS in «DTC P0171: FUEL TRIM SYSTEM LEAN»(ref-152429-S11321185262003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article. Rich The Long Term Fuel Trim will be less than -20 percent. Refer to DIAGNOSTIC AIDS in «DTC P0172: FUEL TRIM SYSTEM RICH»(ref-152429-S11810496972003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
Test the fuel pressure while the condition exists. See «FUEL SYSTEM DIAGNOSIS»(ref-152779-S03797432242003031100000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check Evaporative Emission (EVAP) control system. See «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(ref-152779-S07851640532003022500000) under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING article.
Test the fuel injectors for leaking. See «FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL»(ref-152779-S08897027942003022500000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.

Ignition System

Test for the proper secondary voltage output with Spark Tester (J 26792), or equivalent.
Inspect the spark plugs for correct operation and good ignition system performance.
Inspect the ignition coil boots for damage.
Observe the IAC MOTOR COMMAND parameter on the scan tool at idle, while operating rear defogger, A/C system, or headlights. IAC MOTOR COMMAND parameter should increase 2-7 percent when operating the engine loads. If IAC MOTOR COMMAND parameter remains fixed, check for a short to ground in the Diagnostic Request circuit from the PCM to Data Link Connector (DLC) terminal No. 13.

Inspect for the following engine mechanical conditions: Any faulty hydraulic lifter assemblies. Any broken or weak valve springs. A low compression. An incorrect valve timing. Any sticking or leaking valves. An incorrect or worn camshaft.
See DIAGNOSTIC STARTING POINT - ENGINE MECHANICAL in appropriate ENGINES article.

Check for vacuum leaks. Vacuum leaks can cause a higher than normal idle speed.
Verify the PCM grounds are in the proper locations, with clean, tight connections.
Check scan tool to determine if PCM is receiving an A/C signal. Idle speed should be increased with A/C ON. See «ELECTRICAL/ACCESSORY LOAD IDLE-UP SIGNAL»(ref-152779-S14872662232003031200000) under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Inspect the battery cables and the ground straps. Ensure they are clean and tight.
Inspect A/C refrigerant pressure for being too high or for a faulty high pressure switch. See appropriate MANUAL A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
Test for the proper operation of the IAC system. See «IDLE AIR CONTROL SYSTEM»(ref-152779-S24717997382003022500000) under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
The engine will run rough and the engine can stall if the Camshaft Position (CMP) actuator solenoid is advancing camshaft timing at idle. Inspect for a fully energized or stuck CMP actuator solenoid. If the operation of the CMP actuator solenoid is suspect, see «DTC P1349: INTAKE CMP SYSTEM PERFORMANCE»(ref-152429-S18074355752003020400000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
Check Positive Crankcase Ventilation (PCV) valve for correct operation and the correct part.
Inspect that the idle speed is increasing for changes in electrical loads on the engine. See «ELECTRICAL/ACCESSORY LOAD IDLE-UP SIGNAL»(ref-152779-S14872662232003031200000) under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Verify PCM is increasing the idle speed when P/S system pressure is increased on turns. See «ELECTRICAL/ACCESSORY LOAD IDLE-UP SIGNAL»(ref-152779-S14872662232003031200000) under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check for broken or worn motor and transmission mounts

DIESELING, RUN-ON

Engine continues to run when turning the ignition OFF, but runs very roughly. If the engine runs smoothly, check the ignition switch and adjustment.

See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-152429-S10298708072003020400000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 1.8L VIBE article.

Check the Evaporative Emission (EVAP) control system. See «EVAPORATIVE EMISSION CONTROL SYSTEM DIAGNOSIS»(ref-152779-S17488005022003022500000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check the fuel injectors for leaking. See «FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL»(ref-152779-S08897027942003022500000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.

BACKFIRE

The fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.

See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-152429-S10298708072003020400000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 1.8L VIBE article.
See «SYMPTOMS - ENGINE CONTROLS»(ref-153013-S31152167912003031100000) .

Check for the proper ignition coil output voltage with Spark Tester (J 26792), or equivalent.
Inspect the spark plugs for correct operation and good ignition system performance.
Inspect the ignition coil boots for damage.

Engine Mechanical Checks

Check for any of the following engine mechanical problems: Any broken or weak valve springs. A low compression. Any sticking or leaking valves. An incorrect valve timing. An incorrect or worn camshaft.
Check the intake and the exhaust system for casting flash or other restrictions.

RESTRICTED EXHAUST

INTERMITTENT CONDITIONS

See PRELIMINARY CHECKS under SYMPTOMS - ENGINE CONTROLS.

The fault must be present to be diagnosed correctly with a DTC procedure. If the fault that set the DTC is intermittent, then the use of DTC procedures may result in replacement of good parts.

Control Module Power & Grounds, & Component Power & Grounds

Poor power or ground connections can cause widely varying symptoms.

Test all control module power circuits. Many vehicles have multiple circuits supplying power to the control module. Other components in the system may have separate power circuits that may also need to be tested. Check connections at the module or component connectors, fuses, and any intermediate connections between the power source and the module or component. A test light or a Digital Multimeter (DMM) may indicate that voltage is present, but neither tests the ability of a circuit to carry sufficient current. Ensure that the circuit can carry the current necessary to operate the component.
Check all control module ground and system ground circuits. The control module may have multiple ground circuits. Other components in the system may have separate grounds that may also need to be tested. Check grounds for clean and tight connections at the grounding point. Check connections at the component and in splice packs, where applicable. Ensure the circuit can carry current necessary to operate the component.

Temperature Sensitivity

An intermittent condition may occur when a component or connection reaches normal operating temperature. The condition may occur only when the component or connection is cold, or only when the connection is hot.
The following data may help to diagnose this type of intermittent condition: Freeze Frame/Failure Records. Scan tool snapshot. Vehicle data recorder.
If the intermittent is related to heat, review the following data: High ambient temperatures. Underhood or engine generated heat. Circuit generated heat due to a poor connection, or high electrical load. Higher than normal load conditions, such as towing.
If the intermittent is related to cold, review the following data: Low ambient temperatures. In extremely low temperatures, ice may form in a connection or component. Check for water intrusion. The condition only occurs on a cold start. The condition is not present after the vehicle warms up.
Information from the customer may help to determine if the trouble follows a temperature related pattern.

Duplicating Failure Conditions

If none of the previous tests are successful, attempt to duplicate or capture the failure conditions.
Freeze frame/failure records data, where applicable, contain conditions present when the DTC set. Perform the following procedure: Review and record freeze frame/failure records data. Use scan tool to clear DTCs. Turn the key to OFF and wait 15 seconds. Operate the vehicle under the same conditions that were noted in freeze frame/failure records data, as closely as possible. The vehicle must also be operating within the conditions for running the DTC. Monitor DTC Status for DTC being tested. The scan tool will indicate RAN, when the enabling conditions have been satisfied long enough for the DTC to run. The scan tool will also indicate whether the DTC passed or failed.
An alternate method is to drive vehicle with Digital Multimeter (DMM) connected to a suspected circuit. An abnormal reading on the DMM when problem occurs, may help you locate the problem.

Intermittent Malfunction Indicator Light

The following conditions may cause intermittent MIL operation with no DTCs stored

A defective relay, control module driven solenoid, or a switch that causes electrical system interference. Usually the symptom will occur when the faulty component is operating.
Any Ignition Control (IC) wires routed near the generator or near secondary ignition system wires and components.
An ignition system secondary voltage that is arcing and shorting to ground.
Any poor ignition control circuit or ignition module grounds.
A MIL control circuit that is intermittently shorting to ground.
Any faulty diodes in the generator or charging system circuits.
Improper installation of add-on electrical devices. These can include alarm systems, 2-way radios, lighting systems, electrical motors.

Check for faulty PCM grounds.
Check for open diodes (A/C clutch, charging system, etc.) that may cause electrical interference.
The improper installation of add-on electrical devices. These can include alarm systems, 2-way radios, lighting systems and electrical motors.
If the intermittent fault is believed to involve a particular sensor or component, observe sensor or component display on a scan tool while moving the connectors and wiring harnesses related to the sensor or component. A change in scan tool display can indicate location of the fault.

Engine Control System - Trouble Shooting - No Codes: Other Pontiac Vibe I