E049

TEST CONDITIONS
1. Codes EO13, EO14, EO15, EO17, EO21, EO22, EO24, EO31, EO32, EO34, EO42, EO43, EO44, and EO45 not set;
2. Fuel control in closed loop operation;
3. Vehicle speed equal to 0 MPH;
4. Coolant between 80°C and 110°C;
5. RPM between 400 and 1000;
6. TPS between 20 and 150;
7. Left oxygen sensor toggling more than 3 times per second.

FAILURE CONDITIONS
1. Fuel control integrators don't respond to AIR flow moving from catalytic converter to exhaust manifold to air cleaner. (Failure must occur 2 out of 3 times per ignition cycle.)

ACTION TAKEN:
1. ECM logs a Code EO49 in memory (does not turn on telltale);
2. ECM disables AIR for entire ignition cycle.

DESCRIPTION
Code EO49 is designed to detect AIR system electrical and flow faults by watching the oxygen sensor react to AIR flow. After the fuel control system is in closed loop and AIR is directed to the catalytic converter, the ECM directs AIR to the exhaust parts and waits for the left fuel integrator to show lean operation as the excess oxygen is blown on the oxygen sensor. After a specified period of time, AIR is then diverted to the air cleaner and the ECM watches the left integrator for rich movement as the excess oxygen is taken away from the oxygen sensor.

Code EO49 is only tested under certain engine operating conditions as specified in the test conditions. It is important that proper oxygen sensor operation is verified before performing this chart since Code EO49 depends heavily upon oxygen sensor operation for testing.

Notes on Intermittents
If Code EO49 is stored as an intermittent failure, verify proper operation of the oxygen sensors by using Chart A-7 in ECM Diagnostic Charts. Related Tests, Information and Procedures
Perform the AIR system operation check. Check for AIR valve sending air to the exhaust manifold and catalytic converter. Watch ECM parameter ED36 while driving. If the parameter goes from 128 to 150 or higher, check for improper air flow to the exhaust manifold.

Checking all wiring and connections for intermittent connections. Check AIR management hoses and pipes for improper connections, cut, or rusted through pipes, or restricted passages.

Notes on Fault Tree
1. Checking for ECM control of AIR divert solenoid. Voltmeter should read 12 volts and 0 volts every 3 seconds.
2. Resistance of AIR solenoid should be greater than 20 ohms.