Engine Co/HC Emission Testing: 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
1. 40 cm (1.3 ft) INTO TAILPIPE DURING IDLING
Fig 1: Inserting CO/HC Meter Testing Probe
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
IMMEDIATELY CHECK CO/HC CONCENTRATION AT IDLE AND/OR 2,500 RPM
NOTE: When performing the 2 mode (2,500 RPM and idle) test, follow the measurement orders are prescribed by the applicable local regulations.
If the CO/HC concentration does not comply with regulations, perform troubleshooting in the order given below.
1. Check the heated oxygen sensors operation.
  (See DTC P0130 OXYGEN SENSOR CIRCUIT (BANK 1 SENSOR 1), DTC P0150 OXYGEN SENSOR CIRCUIT (BANK 2 SENSOR 1), DTC P2195 OXYGEN SENSOR SIGNAL STACK LEAN (BANK 1 SENSOR 1), DTC P2196 OXYGEN SENSOR SIGNAL STACK RICH (BANK 1 SENSOR 1), DTC P2197 OXYGEN SENSOR SIGNAL STACK LEAN (BANK 2 SENSOR 1), DTC P2198 OXYGEN SENSOR SIGNAL STACK RICH (BANK 2 SENSOR 1) )
2. See the table below for possible causes, and then inspect and correct the applicable causes if necessary.
Fig 2: CO/HC Problem & Causes Table
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002