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Engine Controls - System & Component Testing: Other Pontiac Aztek I

Testing & Diagnostics ~1690 words

COMPUTERIZED ENGINE CONTROLS

Note. For component locations, see COMPONENT LOCATIONS .

POWERTRAIN CONTROL MODULE

Note. To identify circuits referenced in the following ground and power tests, see WIRING DIAGRAMS or (Схема №12) - (Схема №17).

Ground Circuits

Check PCM connectors for corroded or loose connections. Repair as necessary. Disconnect PCM connectors. Using DVOM, measure resistance between negative battery terminal and ground terminals at PCM harness connector. If resistance is more than 5 ohms, repair open in affected ground circuit. If resistance is 5 ohms or less, ground circuits are okay.

Power Circuits

  1. Check PCM connectors for corroded or loose connections. Repair as necessary. Disconnect PCM connectors. Using DVOM, check for battery voltage between chassis ground and continuous power terminal(s) at PCM harness connector(s). See «WIRING DIAGRAMS»(ref-153136-S10222369522003112400000) . If battery voltage is present, go to next step. If battery voltage is not present, check for open fuse or fusible link. If fuse or fusible link is okay, check for open in wire between PCM terminal and power source.
  2. Turn ignition switch to RUN position. Using DVOM, check for battery voltage between chassis ground and ignition power terminals at PCM harness connector(s). If battery voltage is present, power circuits are okay. If battery voltage is not present, check IGN fuse. If fuse is okay, check for an open in wire between battery and ignition switch, and between ignition switch and PCM terminal. If wiring is okay, check for a defective ignition switch.

SENSORS & SWITCHES

Note. For component locations, see COMPONENT LOCATIONS .

Note. For additional sensor testing specifications, see SENSOR OPERATING RANGE CHARTS - TRUCKS article.

Manufacturer does not provide testing procedures for many individual systems and components. For sensor and switch testing not listed, perform related DTC testing procedure. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

BAROMETRIC PRESSURE SENSOR

A malfunction in Barometric Pressure (BARO) sensor can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

CAMSHAFT POSITION SENSOR

A malfunction in Camshaft Position (CMP) sensor can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

CRANKSHAFT POSITION SENSOR

A malfunction in Crankshaft Position (CKP) sensor can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

ENGINE COOLANT TEMPERATURE SENSOR

A malfunction in Engine Coolant Temperature (ECT) sensor circuit can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. An out-of-calibration ECT sensor may not set a DTC. Use the following procedure to test sensor calibration.

Disconnect ECT sensor harness connector. See COMPONENT LOCATIONS . Using DVOM, measure resistance of ECT sensor at specified temperatures. See SENSOR TEMPERATURE VS RESISTANCE table. Resistance should be high when engine is cold and drop as engine warms. With vehicle sitting overnight, IAT sensor and ECT sensor should have close to the same resistance reading. If resistance is not within specification, replace ECT sensor.

Temperature - °F (°C)(1) Ohms
302 (150)47
284 (140)60
266 (130)77
248 (120)100
230 (110)132
212 (100)177
194 (90)241
176 (80)332
158 (70)467
140 (60)667
122 (50)973
113 (45)1188
104 (40)1459
95 (35)1802
86 (30)2238
77 (25)2796
68 (20)3520
59 (15)4450
50 (10)5670
41 (5)7280
32 (0)9420
23 (-5)12,300
14 (-10)16,180
5 (-15)21,450
4 (-20)28,680
22 (-30)52,700
40 (-40)100,700
(1) Measure resistance across sensor terminals.
(1)Measure resistance across sensor terminals.

SENSOR TEMPERATURE VS RESISTANCE

FUEL LEVEL SENSOR

A malfunction in fuel level sensor circuit can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

FUEL TANK PRESSURE SENSOR

A Fuel Tank Pressure (FTP) sensor circuit can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

HEATED OXYGEN SENSOR

A malfunction in Heated Oxygen Sensor (HO2S) circuit can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

INTAKE AIR TEMPERATURE SENSOR

A malfunction in IAT sensor circuit can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. An out-of-calibration IAT sensor may not set a DTC. Use the following procedure to test sensor calibration.

Disconnect IAT sensor harness connector. See COMPONENT LOCATIONS . Using DVOM, measure resistance of IAT sensor at specified temperatures. See SENSOR TEMPERATURE VS RESISTANCE table. Resistance should be high when air temperature is cold and drop as air temperature warms. With vehicle sitting overnight, ECT sensor and IAT sensor should have close to the same resistance reading. If resistance is not within specification, replace IAT sensor.

KNOCK SENSOR

A malfunction in Knock Sensor (KS) circuit can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

MANIFOLD ABSOLUTE PRESSURE SENSOR

A malfunction in Manifold Absolute Pressure (MAP) sensor circuit can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

MASS AIRFLOW SENSOR

A malfunction in Mass Airflow (MAF) sensor circuit can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

THROTTLE POSITION SENSOR

Note. Throttle Position (TP) sensor is not adjustable. Replace TP sensor as necessary.

A malfunction in TP sensor circuit can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

TRANSMISSION RANGE SWITCH

See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.

VEHICLE SPEED SENSOR

See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.

MODULES, MOTORS, RELAYS & SOLENOIDS

Note. Manufacturer does not provide testing procedures for many individual systems and components. For module, motor, relay and solenoid testing not listed, perform related DTC testing procedure. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

Note. For component locations, see COMPONENT LOCATIONS .

A/C COMPRESSOR CLUTCH RELAY

See appropriate AUTOMATIC A/C-HEATER SYSTEMS or MANUAL A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.

FUEL PUMP RELAY

See FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS.

IDLE AIR CONTROL VALVE

See IDLE AIR CONTROL SYSTEM DIAGNOSIS under IDLE CONTROL SYSTEM.

FUEL SYSTEMS

Note. For component locations, see COMPONENT LOCATIONS .

IDLE CONTROL SYSTEM

Note. For component locations, see COMPONENT LOCATIONS .

IGNITION SYSTEMS

Note. For ignition system testing, perform related DTC testing procedure. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

Note. For a no-start problem, refer to NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.

See CAMSHAFT POSITION SENSOR under SENSORS & SWITCHES.

See CRANKSHAFT POSITION SENSOR under SENSORS & SWITCHES.

EMISSION SYSTEMS & SUB-SYSTEMS

Note. For emission and sub-system testing not listed, perform related DTC testing procedure. DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

Electric AIR Pump

Note. For electric AIR pump testing, perform related DTC testing procedure. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

EXHAUST GAS RECIRCULATION

Note. For EGR system diagnosis, see appropriate INSPECTION/MAINTENANCE PROCEDURES under DRIVE CYCLES in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

FUEL EVAPORATION

Note. Ensure all vacuum line and EVAP system components are not damaged or missing before proceeding with this test.

Required Service

The PCV system may require service for obstructions if any of the following conditions exist

  1. Rough idle.
  2. Stalling or low idle speed.
  3. Oil leaks.
  4. Oil in air cleaner.
  5. Sludge in engine.

A leaking PCV valve or hose could cause

  1. Rough idle.
  2. Stalling.
  3. High idle speed.

If engine idles rough, check for clogged PCV valve, or for plugged or broken PCV hoses BEFORE adjusting idle. Check PCV valve application to ensure valve is fitted. Replace PCV valve if required.

Checking PCV Valve Function

  1. Disconnect PCV valve vacuum hose from cylinder head cover. Run engine at idle. Place thumb over open end of PCV valve vacuum hose to check for vacuum. If vacuum does not exist, check for obstruction in source vacuum supply. If source vacuum supply is okay, replace PCV valve.
  2. Turn ignition off. Remove PCV valve. Shake valve and listen for rattle of check valve inside PCV valve. If a clear rattle is not heard, replace PCV valve.
  3. Visually inspect valve for varnish or deposits that may make PCV valve operation sticky or restricted, or cause incomplete seating of valve. Replace as necessary.
  4. Engine must be sealed for PCV system to function as designed. If leakage, sludging or dilution of oil is noted and PCV system is functioning properly, check engine for cause and repair as required to ensure PCV system will continue to function properly.
  5. An engine operating without any crankcase ventilation can be damaged, so it is important to replace PCV valve and air cleaner breather (if equipped) at regular intervals (at least every 30,000 miles). Check all hoses and clamps for failure or deterioration.

MISCELLANEOUS CONTROLS

Note. Although some of the controlled devices listed here are not technically engine performance components, they can affect driveability if they malfunction.

Manufacturer does not provide testing procedures for many individual systems and components. For system and component testing not listed, perform related DTC testing procedure. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

A/C COMPRESSOR CLUTCH CONTROLS

Note. For A/C compressor clutch circuit testing, see appropriate AUTOMATIC A/C-HEATER SYSTEMS or MANUAL A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. See appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL for terminal and wire color identification.

ELECTRIC COOLING FAN CONTROL

Note. For electric cooling fan circuit testing, see ELECTRIC COOLING FANS article in AIR CONDITIONING & HEATING. See appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL for terminal and wire color identification.

TRANSMISSION

Note. For transmission electronic controls and component testing, see appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS. For component circuit identification, see appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

AZTEK

For wiring diagrams, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

RENDEZVOUS

For wiring diagrams, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.