Engine Co/HC Inspection: Co/HC: Inspection

NOTE:

This check is used only to determine whether or not the idle CO/HC complies with regulations.

Initial conditions.
1. Engine at normal operating temperature
2. Air cleaner installed
3. All pipes and hoses of air induction system connected
4. All accessories switched OFF
5. All vacuum lines properly connected
6. SFI system wiring connectors fully plugged
7. Ignition timing checked correctly
8. Transmission in neutral position
9. Tachometer and CO/HC meter calibrated by hand
Start engine.
Race engine at 2,500 rpm for approx. 180 seconds.
Insert CO/HC meter testing probe at least 40 cm (1.3 ft) into tailpipe during idling.
Immediately check CO/HC concentration at idle and/or 2,500 rpm.
NOTE:
When doing the 2 mode (2,500 rpm and idle) test, follow the measurement order prescribed by the applicable local regulations.

Fig 1: Inserting CO/HC Meter Testing Probe Into Tail Pipe
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Troubleshooting.
If the CO/HC concentration does not comply with regulations, troubleshoot in the order given below.
1. Check oxygen sensor operation (See DTC P0136: HEATED OXYGEN SENSOR CIRCUIT MALFUNCTION (BANK1 SENSOR2) ).
2. Check A/F sensor operation (See DTC P1130: AIR/FUEL SENSOR CIRCUIT RANGE/PERFORMANCE MALFUNCTION (BANK1 SENSOR1) ).
3. See the table below for possible causes, then inspect and correct the applicable causes if necessary
Fig 2: Displaying Possible Causes
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002