5.0l VIN [e] Tbi "a" Charts Chevrolet Camaro III рестайлинг

MODEL IDENTIFICATION

Repair procedures in this article are sometimes identified by a specific body code. The following table lists GM division, model name, and body types that apply to the body codes.

MODEL IDENTIFICATION

DESCRIPTION

The computerized engine control system monitors as many as 19 engine/vehicle functions. (Scheme 219) This system controls engine operation and lowers exhaust emissions while maintaining fuel economy and driveability. The Electronic Control Module (ECM) is the "brain" of the CCC system.

The computerized engine control system is primarily an emission control system, designed to maintain a 14.7:1 air/fuel ratio under all operating conditions. When the ideal air/fuel ratio is maintained, the 3-way catalytic converter can control Oxides of Nitrogen (NOx), Hydrocarbon (HC) and Carbon Monoxide (CO) emissions.

ECM Conditions Sensed & Systems Controlled. Scheme 219

SPECIAL DIAGNOSTIC TOOLS

Note. Special "Scan" testers plugged into the ALDL may be used to read trouble codes and check voltages in the system on the serial data line (terminal "E") These testers can save a great deal of time. For additional information see SCAN TESTER USAGE and SCAN TESTER - TEST DATA PARAMETERS tables in this article.

The computerized engine control system is most easily diagnosed using a "Scan" tester, however, other tools may aid in diagnosing problems if a "Scan" tester is unavailable. These tools are: a tachometer, test light, ohmmeter, digital voltmeter with 10-megohm impedance (minimum), vacuum pump, vacuum gauge, fuel injector test lights (TBI and PFI) and 6 jumper wires 6" long (one wire with female connectors at both ends, one wire with male connector at both ends and 4 wires with male and female connectors at opposite ends). A test light, rather than a voltmeter, must be used when indicated by a diagnostic chart.

SCAN TESTER USAGE

Note. Prior to connection of scan tester to vehicle, diagnostic system should be checked to determine if system is operating properly and if information received by scan tester will be accurate. This is done by performing appropriate DIAGNOSTIC CIRCUIT CHECK for that system. If vehicle does not pass diagnostic circuit check, information received by scan tester may be invalid. CCC Scan tester is a specialized tester which, when plugged into ALDL, can be used to diagnose on-board computer control stems by providing instant access to circuit voltage information without need to crawl under dash or hood to back-probe sensors and connectors.

Scan testers cut down diagnostic time dramatically by furnishing input data (voltage signals) which can be compared to specification parameters. See SCAN TESTER - TEST DATA PARAMETERS table in this article. They also furnish information on output device (solenoids and motors) status. Status parameters, however, are only an indication that output signals have been sent to devices by the ECM. It does not indicate if devices have responded properly to that signal. This will need to be verified at output device using a voltmeter or test light.

Note. Code 12 should always exist when ALDL is grounded with key on and engine not running but may not be indicated by all makes of scan tester.

If trouble codes are not present, this is not an indication that there is not a problem. CCC related problems are about 20 percent codes and 80 percent driveability. Sensors that are out of specification WILL NOT set a trouble code but WILL cause driveability problems. Use of a scan tester is easiest method of checking sensor specifications and other data parameters. Tester is also useful in finding intermittent wiring problems by wiggling wiring harnesses and connections (key on, engine off) while observing data parameters. See SCAN TESTER - TEST DATA PARAMETERS table in this article.

Note. Information obtained by scan tester is only as accurate as the tester itself. If erroneous voltage signals are suspected, it will be necessary to verify tester information using a digital voltmeter and wiring schematic. If non- existent codes are in evidence, turn ignition off, remove tester, turn ignition on and ground ALDL "DIAGNOSTIC TERMINAL". If same codes are not flashed by "SERVICE ENGINE SOON" light that were indicated by scan tester, tester cannot be used on vehicle and information obtained by it will not be guaranteed accurate.

SCAN TESTER - TEST DATA PARAMETERS

Note. Information in the following table is typical readings taken on vehicle with engine idling, upper radiator hose hot, closed throttle, transmission in Park or Neutral, "closed loop" status achieved and all accessories off (except as noted in tables). Data parameters are updated every 1 1/4 seconds. On systems using P-4 computers, parameter updates are virtually instantaneous. Not all devices & systems are used on all models.

THROTTLE BODY INJECTION

"NON-SCAN" DIAGNOSTIC CIRCUIT CHECK

The diagnostic circuit check is an organized approach for identifying a problem caused by the fuel injection system. Driver complaints fall into 3 categories: steady "SERVICE ENGINE SOON" light, driveability problems, and "engine cranks, but will not run". Understanding chart and using it correctly will reduce diagnostic time and prevent unnecessary replacement of parts.

Note. The following step numbers refer to the numbers in the accompanying flow chart(s).

1. A steady "SERVICE ENGINE SOON" light with ignition on and engine not running confirms battery and ignition voltage to Electronic Control Module (ECM).
2. Ground diagnostic test terminal by connecting a jumper wire between terminals "A" and "B" in assembly line communication link (ALCL) connector, located below instrument panel. The ECM will cause "SERVICE ENGINE SOON" light to flash Code 12, indicating that ECM diagnostics are working. Code 12 will flash 3 times, followed by other trouble codes stored in memory. Each additional code will flash 3 times, starting with lowest code, and then start over again with Code 12. If there are no other codes, Code 12 will flash until diagnostic test terminal jumper is disconnected or engine is started.
3. Record all stored codes, except Code 12. If the problem is "engine cranks but will not run", proceed to CHART A3.
4. If no additional codes were recorded, see TROUBLE SHOOTING procedures in CEC TESTS W/O CODES article in this section for driveability symptoms and recommended service procedures. With engine running and diagnostic terminal grounded, the ECM will respond to the oxygen sensor signal and use the "SERVICE ENGINE SOON" light to display the following information: Closed loop confirms that oxygen sensor signal is being used by the ECM to control fuel delivery and that system is working properly. Signal voltage will vary from below .35 to above .55 volts. Open loop indicates that oxygen sensor signal is not useable to ECM. Signal voltage will be constant and between .35 and .55 volts. System will flash "open loop" for 30 seconds to 2 minutes after engine starts or until sensor reaches normal operating temperature. If system fails to go into closed loop, see Code 13 test. "SERVICE ENGINE SOON" light off indicates that exhaust is lean. Oxygen sensor will be less than .35 volts and steady. See Code 44 test procedures. "SERVICE ENGINE SOON" light on steady indicates that exhaust is rich. Oxygen sensor signal will be above .55 volts and steady. See Code 45 test procedures.
5. Road test of the system in the field service mode should be done only at steady road speeds. The following conditions may be observed and should be considered normal: light on too long under acceleration, light off too long under deceleration or light on too long with idle below 1200 RPM.
6. To clear codes, turn ignition off and disconnect battery pigtail for 10 seconds

"Non-Scan" Diagnostic Circuit Check. Scheme 220

"SCAN" DATA DIAGNOSTIC CIRCUIT CHECK

The Diagnostic Circuit Check is an organized approach to identifying a problem created by an Electronic Engine Control System (EECS) malfunction. It must be the starting point for driveability complaint diagnosis, because it directs the service technician to the next logical step in diagnosing the complaint.

The "SCAN DATA" chart may be used for comparison, after completing the diagnostic circuit check and finding the on-board diagnostics functioning properly and no trouble codes displayed. The typical values are an average of display values recorded from normally operating vehicles and are intended to represent what a normally functioning system would typically display.

Note. A "SCAN" tester that displays faulty data should not be used, and the problem should be reported to the manufacturer. The use of a faulty "SCAN" tester can result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed are used in this article for diagnosis. If a "SCAN" tester reads other parameters, the values are not recommended by General Motors for use in diagnosis.

"Scan" Data Diagnostic Circuit Check. Scheme 221

CHART A1 - NO "SERVICE ENGINE SOON" LIGHT

There should always be a steady "SERVICE ENGINE SOON" light, when the ignition is on and engine stopped. Battery voltage is supplied directly to the light. The electronic control module (ECM) will control the light and turn it on by providing a ground path through circuit No. 419 to the ECM.

Note. Test numbers refer to test numbers on diagnostic chart.

1. Battery voltage at circuit No. 340 is protected by a 20-amp in-line fuse. If this fuse was blown, refer to wiring schematic for Code 54 test procedures.
2. Using a test light connected to 12 volts, probe each of the system ground circuits to be sure a good ground is present. See ECM terminal end view in this article.

Diagnostic Aids

ENGINE RUNS OKAY, CHECK THE FOLLOWING

1. Faulty light bulb.
2. Circuit No. 419.
3. Gauge fuse blown. This will result in no oil, or alternator lights, seat belt reminder etc.

CRANKS, BUT WILL NOT RUN, CHECK THE FOLLOWING

1. Continuous battery drain-fuse or fusible link open.
2. ECM ignition fuse open.
3. Battery circuit No. 340-to-ECM open.
4. Ignition circuit No. 439 to ECM open.
5. Poor connection to ECM.

Chart A1 Schematic, No "Service Engine Soon" Light. Scheme 222

Flow Chart A1, No "Service Engine Soon" Light. Scheme 223

Flow Chart A1, No "Service Engine Soon" Light. Scheme 224

WON'T FLASH CODE 12 "SERVICE ENGINE SOON" ("SES") LIGHT ON STEADY

There should always be a steady "SERVICE ENGINE SOON" light, when ignition is on and engine stopped. Battery voltage is supplied directly to the light bulb. The ECM will turn the light on by grounding circuit No. 419 at the ECM. With the diagnostic terminal grounded, the light should flash a Code 12, followed by any trouble Code stored. A steady light could be a short to ground in light control circuit No. 419, or an open in diagnostic circuit No. 451.

Note. Test numbers refer to test numbers on diagnostic chart.

1. If there is problem with the ECM that causes a "SCAN" tester not read "Serial Data", then the ECM should not flash a Code 12. If Code 12 does flash, be sure that the "SCAN" tester is working properly on another vehicle. If the "SCAN" tester is functioning properly and circuit No. 461 is okay, the Mem-Cal or ECM may be at fault for the NO ALDL.
2. If the light goes off when the ECM connector is disconnected, then circuit No. 419 is not shorted to ground.
3. This test checks for an open diagnostic circuit No. 451.
4. At this point, the "SERVICE ENGINE SOON" light wiring is okay. The problem is a faulty ECM or PROM. If code 12 does not flash, the ECM should be replaced using the original PROM. Replace the PROM only after trying an ECM, as a defective PROM is an unlikely cause of the problem.

Flow Chart A2, Won't Flash Code 12, "SES" Light On Steady. Scheme 225

Flow Chart A2, Won't Flash Code 12, "SES" Light On Steady. Scheme 226

CHART A3 (1 OF 2) - ENGINE CRANKS BUT WON'T RUN

Note. Before performing this test, check battery condition (12 volts), engine cranking speed, and for adequate fuel in tank.

Note. Test numbers refer to test numbers on diagnostic chart.

1. A "SERVICE ENGINE SOON" light on is a basic test to determine if there is a 12-volt supply to the ECM. No ALDL may be due to an ECM problem and CHART A2 will diagnose the ECM. If TPS is over 2.5 volts, the engine may be into the clear flood mode which will cause starting problems. The engine will not start without reference pulses and therefore, the "SCAN" tester should read RPM (reference) during cranking.
2. No spark may be caused by one of several components related to the ignition system. CHART C-4 will address all problems related to the causes of a no spark condition.
3. Fuel spray from the injectors indicates that fuel is available. However, the engine could be severely flooded due to too much fuel.
4. While cranking engine, there should be no fuel spray with injector disconnected. Replace an injector if it sprays fuel or drips like a leaking water faucet.
5. The fuel pressure will drop after the fuel pump stops running due to a controlled bleed in the fuel system. Use of the fuel pressure gauge will determine if fuel system pressure is enough for engine to start and run.
6. No fuel spray from injector indicates a faulty fuel system or no ECM control of injector.
7. This test will determine if the ignition module is not generating the reference pulse, of if the wiring or ECM are at fault. Using a test light connected to 12-volts, touch circuit No. 430, a reference pulse should be generated. If injector test light blinks, the ECM and wiring are okay.

Water or foreign material can cause a no start during freezing weather. An EGR sticking open can cause a low air/fuel ratio during cranking. Low fuel pressure can result in a very lean/air fuel ratio. A grounded circuit No. 423 (EST) may cause a no start or a start then stall condition.

Chart A3 Schematic, Cranks But Won't Run ("B" & "G" Bodies). Scheme 227

Chart A3 Schematic, Cranks But Won't Run ("F" Body). Scheme 228

Flow Chart A3, Engine Cranks But Won't Run (1 of 2). Scheme 229

Flow Chart A3, Engine Cranks But Won't Run (1 of 2). Scheme 230

CHART A3 (2 OF 2) - ENGINE CRANKS BUT WON'T RUN

This test assumes that battery condition and engine cranking speed are okay, and there is adequate fuel in the tank.

Note. Test numbers refer to test numbers on diagnostic chart.

1. No fuel spray from one injector indicates a faulty fuel injector or no ECM control of injector. If the test light blinks while cranking, then ECM control should be considered okay. Be sure test light makes good contact between connector terminals during test. The light may be a little dim when its blinking. This is due to current draw of the test light. How bright the blinks is not important.
2. Circuits No. 481 and 482 supply ignition voltage to the injectors. Probe each connector terminal with test light to ground. There should be a light on at one terminal. If the test light confirms ignition voltage at the connector, the ECM injector control circuits No. 467 and 468 may be open. Reconnect the injector and using a test light connected to ground, check at the applicable ECM connector terminal "D14" or "D16". A light at this point indicates that the injector drive circuit is okay. If an ECM repeat failure has occurred, the injector is shorted. Replace the injector and ECM.

Flow Chart A3, Engine Cranks But Won't Run (2 of 2). Scheme 231

Flow Chart A3, Engine Cranks But Won't Run (2 of 2). Scheme 232

CHART A7 (1 OF 2) - FUEL SYSTEM DIAGNOSIS

When the ignition switch is on, the ECM will turn on the in-tank fuel pump. It will remain on as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.

If there are no reference pulses, the ECM will shut off the fuel pump within 2 seconds after the key is turned on. The pump will deliver fuel to the TBI unit, where the system pressure is controlled to 9-13 psi (6.2-9.0 kg/cm 2 ). Excess fuel is then returned to the fuel tank. The fuel pump test terminal is located in the left side of the engine compartment. When the engine is stopped, the pump can be turned on by applying battery voltage to the test terminal.

Note. Test numbers refer to test numbers on diagnostic chart.

1. Fuel pressure should be noted while fuel pump is running. Fuel pressure will drop immediately after fuel pump stops running due to a controlled bleed in the fuel system.

Improper fuel system pressure can result in of the following problems

CRANKS, BUT WON'T RUN.

1. Code 44.
2. Code 45.

CUTS OUT, MAY FEEL LIKE AN IGNITION PROBLEM.

1. Poor fuel economy, loss of power.
2. Hesitation.

Chart A7 - Electrical Schematic, Fuel System Diagnosis. Scheme 233

Chart A7 - Fuel System Schematic. Scheme 234

Flow Chart A7 (1 of 2), Fuel System Diagnosis. Scheme 235

Flow Chart A7 (1 of 2), Fuel System Diagnosis. Scheme 236

CHART A7 (2 OF 2) - FUEL SYSTEM DIAGNOSIS

Note. Test numbers refer to test numbers on diagnostic chart.

1. Has regulated fuel pressure, but pressure is less than 9 psi (.6 kg/cm 2 ). Check the following when this condition occurs: Amount of fuel to injectors is okay, but pressure is too low. Fuel system will be running lean and may set Code 44. Also exhibits hard starting cold and poor overall performance. Has restricted fuel flow causing pressure drop. Normally, a vehicle with a fuel pressure of less than 9 psi (6.2 kg/cm 2 ) at idle will not be driveable. However, if the pressure drop occurs only while driving, the engine will normally surge, then stop, as pressure begins to drop rapidly.
2. Restricting the fuel return line allows the fuel pump to develop its maximum pressure (dead head pressure). When battery voltage is applied to the fuel pump test terminal, pressure should be 13-18 psi (90-124 kg/cm 2 ).
3. This test determines if the high fuel pressure is due to a restricted fuel return line or throttle body pressure regulator malfunction.

Flow Chart A7 (2 of 2) Fuel System Diagnosis. Scheme 237

Flow Chart A7 (2 of 2) Fuel System Diagnosis. Scheme 238

5.0L TBI Component Locations ("F" Body). Scheme 239

5.0L TBI ECM Terminal ID & Pin Voltages ("F" Body). Scheme 240

5.0L TBI CCC Wiring Diagram ("F" Body). Scheme 241