Service Manual2011 Aveo ENGINE CONTROLS

SECTION 1F1

ENGINE CONTROLS - 1.2L DOHC

Caution : Disconnect the negative battery cable before removing or installing any electrical unit o r w hen a tool or equipment could easily come in contact with exposed electrical terminals. Disconnecting this cable will help prevent personal injury and damage to the vehicle. The ignition must also be in LOCK unless otherwise noted.

SPECIFICATIONS

Engine Data Display Tables

Engine Data Display

Parameter	Scaling	Value
Desired Idle Speed	RPM	ECM idle command (varies with temperature)
Engine RPM	RPM	± 50 RPM from desired RPM in drive (A/T) ± 50 RPM from desired RPM in neutral (M/T)
MAP	kPa	29 - 55 (varies with manifold and barometric pressure)
Throttle Position Volt	V	0 v
Start-up IAT	°C	varies
Intake Air Temperature	°C	10 - 90 °C
Coolant Temperature (Start-up)	°C	varies
Engine Coolant Temperature	°C	85 - 105 °C
IAC Motor Position	-	1 - 50
O2 Sensor (B1-S1)	mV	1-1000 mV (varies continuously)
O2 Sensor (B1-S2)	mV	1-1000 mV (varies continuously)
Fuel System Status	Closed Loop/Open Loop	"Closed Loop" (may enter "Open Loop" at extended idle)
Rich/Lean (B1-S1)	Rich/Lean	varies
Lean to Rich Average	mS	10 -211 ms or 0 ms
Rich to Lean Average	mS	10 -211 ms or 0 ms
Engine Load Value	%	0 - 100 % (varies)
Short Term Fuel Trim	%	-30 - 30%
Long Term Fuel Trim	%	-30 - 30%
Linear EGR Feedback	V	varies
EGR Duty Cycle	%	0 %
EGR EWMA Result	-	< = 0
Spark Advance	°	varies
MIL Odometer	Km	0 Km
MIL On Time	Min	0 Min
Base Injection PWM	mS	1.0 - 5.0 ms
Barometric Pressure	kPa	varies with altitude
Ignition Voltage	V	13.5 - 14.8 V
Air/Fuel Ratio	Ratio	14.6 (Closed Loop Enable)
Calculated Air Flow	G/S	varies
Total Misfire (Current)	-	0
Misfire History Cyl. 1	-	0
Misfire History Cyl. 2	-	0
Misfire History Cyl. 3	-	0
Misfire History Cyl. 4	-	0
Vehicle Speed	Km/H	0 Km/H
A/C Pressure	V	varies
A/C Request	Yes/No	No
A/C Clutch	On/Off	Off
Fuel Pump Command	On/Off	On
Closed Loop	Yes/No	Yes
Throttle At Idle	Yes/No	No
O2 Ready (B1-S1)	Yes/No	Yes
Knock Present	Yes/No	No
Fan Low	On/Off	On/Off
Fan High	On/Off	On/Off
TCC Engaged (Only AT)	Yes/No	Yes
Park/Neutral (Only AT)	P/N and R/N/D	P/N
Fuel Level Input	V	varies
Fuel Level Output	%	varies
Fuel Trim Cell	-	18
G-Sensor	V	1.1 - 3.7 V (Non-ABS Only)
Engine Runtime	HH:MM:SS	Hours:Minutes:Seconds

* Condition: Warmed up, idle, park or neutral, A/C off

Engine Data Display Table Definitions

ECM Data Description

The following information will assist in diagnosing emission or driveability problems. A first technician can view the displays while the vehicle is being driven by second technician. Refer to Powertrain On-Board Diagnostic (EOBD) System Check for addition information.

A/C Clutch

The A/C Relay represents the commanded state of the A/C clutch control relay. The A/C clutch should be engaged when the scan tool displays ON.

A/C Pressure

The A/C High Side displays the pressure value of the A/C refrigerant pressure sensor. The A/C High Side helps to diagnose the diagnostic trouble code (DTC) P0533.

A/C Request

The A/C Request represents whether the air conditioning is being requested from the HVAC selector. The input is received by the instrument panel cluster and then sent serial data to the ECM and finally to the scan tool over KWP 2000 serial data.

Air Fuel Ratio

The Air Fuel Ration indicates the air to fuel ratio based on the Front Heated Oxygen Sensor (HO2S1) inputs. The ECM uses the fuel trims to adjust fueling in order to attempt to maintain an air fuel ratio of 14.7:1.

BARO

The Barometric Pressure (BARO) sensor measures the change in the intake manifold pressure which results from altitude changes. This value is updated at ignition ON and also at Wide Open Throttle (WOT).

Base Injection PWM

Indicates the base Pulse Width Modulation (PWM) or ON time of the indicated cylinder injector in milliseconds. When the engine load is increased, the injector pulse width will increase.

Calculated Air Flow

The calculated air flow is a calculation based on manifold absolute pressure. The calculation is used in several diagnostics to determine when to run the diagnostics.

Desired Idle Speed

The ECM commands the idle speed. The ECM compensates for various engine loads in order to maintain the desired idle speed. The actual engine speed should remain close to the desired idle under the various engine loads with the engine idling.

Engine Coolant Temperature

The Engine Coolant Temperature (ECT) sensor sends engine temperature information to the ECM. The ECM supplies 5 volts to the engine coolant temperature sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the ECM monitors a high voltage which it interprets as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal will decrease and the ECM will interpret the lower voltage as a warm engine.

EGR Desired Position

The desired exhaust gas recirculation (EGR) position is the commanded EGR position. The ECM calculates the desired EGR position. The higher the percentage, the longer the ECM is commanding the EGR valve ON.

Engine Load

Indicates engine load based on manifold absolute pressure. The higher the percentage, the more load the engine is under.

Engine Run Time

The engine run time is a measure of how long the engine has been running. When the engine stops running, the timer resets to zero.

Engine Speed

Engine Speed is computed by the ECM from the fuel control reference input. It should remain close to desired idle under the various engine loads with the engine idling.

Fan

The Fan Control (FC) Relay is commanded by the ECM. The FC Relay displays the command as ON or OFF.

Fuel Level Sensor

The Fuel Level Sensor monitors the fuel level in the tank. The Fuel Level Sensor monitors the rate of change of the air pressure in the EVAP system. Several of the Enhanced EVAP System diagnostics are dependent upon the correct fuel level.

Fuel System Status

The Closed Loop is displayed indicating that the ECM is controlling the fuel delivery according to the Front Heated Oxygen Sensor (HO2S1) voltage as close to an air/fuel ratio of 14.7 to 1 as possible.

IAC Position

The scan tool displays the ECM command for the Idle Air Control (IAC) pintle position in counts. The higher the number of counts, the greater the commanded idle speed reads. The Idle Air Control responds to changes in the engine load in order to maintain the desired idle rpm.

Ignition 1 (Voltage)

The ignition volts represent the system voltage measured by the ECM at the ignition feed circuit.

Intake Air Temperature

The ECM converts the resistance of the Intake Air Temperature (IAT) sensor to degrees in the same manner as the engine coolant temperature (ECT) sensor. In take air temperature is used by the ECM to adjust fuel delivery and spark timing according to incoming air density.

Knock Present

The KS Noise Channel indicates when the ECM detects the KS signal. The ECM should display NO at idle.

Long Term FT

The Long Term Fuel Trim (FT) is derived from the short term fuel trim value. The Long Term FT is used for the long term correction of the fuel delivery. A value of 128 counts (0%) indicates that the fuel delivery requires no compensation in order to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced. The ECM is decreasing the injector pulse width. A value above 128 counts indicates that a lean condition exists for which the ECM is compensating.

MAP

The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure which results from engine load and speed changes. As the intake manifold pressure increases, the air density in the intake also increases and the additional fuel is required.

Misfire History #1-4

Indicates the number of misfires that have occurred after 195 current misfires have been counted. The current misfire counter will add its misfires to the history misfire counter after 195 total misfires have taken place. If 1 cylinder is misfiring, the misfiring current counter will have 195 misfires counted before adding to its history counter. If 2 cylinders are misfiring, the misfiring current counter will add to their history counters after 97 misfires. The counter increments only after a misfire diagnostic trouble code (DTC) has been set.

Front Heated Oxygen Sensor

The pre-converter Front Heated Oxygen Sensor (HO2S1) reading represents the exhaust oxygen sensor output voltage. This voltage will fluctuate constantly between 100 mv (lean exhaust) and 900 mv (rich exhaust) when the system is operating in a Closed Loop.

Rear Heated Oxygen Sensor

The post-converter Rear Heated Oxygen Sensor (HO2S2) represents the exhaust oxygen output voltage past the catalytic converter. This voltage remains inactive, or the voltage will appear lazy within a range of 100 mv (lean exhaust) and 900 mv (rich exhaust) when operating in a Closed Loop.

Short Term FT

The Short Term FT represents a short term correction to fuel delivery by the ECM in response to the amount of time the oxygen sensor voltage spends above or below the 450 mv threshold. If the oxygen sensor has mainly been below 450 mv, indicating a lean air/fuel mixture, short term fuel trim will increase to tell the ECM to add fuel. If the oxygen sensor voltage stays mainly above the threshold, the ECM will reduce fuel delivery to compensate for the indicated rich condition.

Spark Advance

This is a display of the spark advance Ignition Coil (IC) calculation which the ECM is programming in the ignition system. It computes the desired spark advance using data such as engine temperature, rpm, engine load, vehicle speed and operating mode.

TCC Engaged

When the brake pedal is applied, the Torque Converter Clutch (TCC) brake switch sends a signal to the ECM to disengage the TCC and disable the cruise control.

Total Misfire Current Counter

Indicates the total number of misfires that have been detected in all the cylinders after 100 engine cycles. One cycle equals one complete 4 stroke cycle. The total misfire only increments during the steady state cruise conditions.

TP Sensor

The ECM uses the TP Sensor in order to determine the amount of the throttle demanded by the vehicle's operator. The TP Sensor reads between 0.36-0.96 volts at idle to above 4 volts at WOT.

Vehicle Speed

The vehicle speed sensor signal is converted into mph or km/h for display. The vehicle speed output from the ECM is 4000 pulses per mile. The scan tool uses the KWP 2000 serial data from the ECM to obtain vehicle speed, while the Instrument Panel Cluster (IPC), cruise control module and the chime alarm module use the 4000 ppm output.

Fastener Tightening Specifications

Application	N•m	Lb-Ft	Lb-In
Accessory Mounting Bracket Bolts	37	27	-
Camshaft Position Sensor Bolts	12	-	106
Crankshaft Position Sensor Retaining Bolt	6.5	-	58
Electronic Ignition System Ignition Coil Retaining Bolts	10	-	89
Exhaust Gas Recirculation Valve Retaining Bolts	30	22	-
Exhaust Gas Recirculation Valve Retaining Bolts (1.2 DOHC)	22	16.2	-
Exhaust Gas Recirculation Valve Retaining Nuts (1.2 DOHC)	10	-	89
Engine Control Module Bracket Retaining Nuts	7	-	62
Engine Coolant Temperature Sensor Bolt (1.2 DOHC)	17.5	12.9	-
Evaporative Emission Canister Flange Bolt	20	16	-
Evaporative Emission Canister Bracket Retaining Bolt	8	-	71
Evaporative Emission Canister Purge Solenoid Bracket Bolt	5	-	44
Evaporative Emission Vent Solenoid Bolt	8.5	-	75
Fuel Filter Mounting Bracket Assembly Bolt	4	-	35
Fuel Pressure Regulator Retaining Screw	12	-	106
Fuel Pump Retaining Bolts (1.2 DOHC)	4	-	35
Fuel Tank Retaining Bolts	20	15	-
Fuel Rail Retaining Bolts	25	18	-
Idle Air Control Valve Retaining Bolts	3	-	27
Knock Sensor Bolt	20	15	-
Temperature-Manifold Absolute Pressure(T-MAP) Sensor Mounting Bracket Bolt	4	-	35
Temperature-Manifold Absolute Pressure(T-MAP) Sensor Retaining Bolts and Nuts	10	-	89
Oil Pressure Switch Fitting	30	22	-
Oxygen Sensor Bolt	42	31	-
Rear A/C Compressor Mounting Bracket Bolts	35	26	-
Spark Plug Cover Bolts	3	-	27
Throttle Body Retaining Nuts	10.5	7.7	-
Throttle Position Sensor Retaining Bolts	2.7	-	23.9

Temperature Vs Resistance

°C	°F	ECT Sensor	IAT Sensor
.	.	OHMS
Temperature vs Resistance Values (Approximate)
100	.	212	177	187
90	194	241	246
80	176	332	327
70	158	467	441
60	140	667	603
50	122	973	837
45	113	1188	991
40	104	1459	1180
35	95	1802	1412
30	86	2238	1700
25	77	2796	2055
20	68	3520	2500
15	59	4450	3055
10	50	5670	3760
5	41	7280	4651
0	32	9420	5800
-5	23	12300	7273
-10	14	16180	9200
-15	5	21450	9200
-20	-4	28680	15080
-30	-22	52700	25600
-40	-40	100700	45300

SPECIAL TOOLS

Special Tools Table

	DW100-010 Gauge-Fuel Pressure Measuring
	EN–48259 Remover/Installer-Oxygen Sensor

EN-49090

Remover/Installer-Fuel Pump Lock Ring