Inspection Procedure

HINT:

• If DTC P0010 displayed, check right bank OCV circuit.
• If DTC P0020 displayed, check left bank OCV circuit.
• Read freeze frame data using OBD II scan tool or hand-held tester. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

hand-held tester: 

1. Check OCV circuit. 

   PREPARATION: 

   1. Start the engine and warmed it up.
   2. Connect the hand-held tester and select the VVT from the ACTIVE TEST menu.

   CHECK: 

   Check the engine speed when operate the OCV by the hand-held tester.

   OK: 

   VVT system is OFF (OCV is OFF): Normal engine speed 

   VVT system is ON (OCV is ON): Rough idle or engine stalled 

   1. OK: Check for intermittent problems (See  PRE-CHECK  ). 
   2. NG: Go to next step. 
2. Check operation of OCV. 

   PREPARATION: 

   1. Start the engine and warmed it up.
   2. Disconnect the OCV connector.
   3. Apply battery positive voltage between terminals of the OCV.

   CHECK: 

   Check the engine speed.

   OK: 

   Rough idle or engine stalled. 

   Fig 1: Applying Battery Positive Voltage Between Terminals Of OCV

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. NG: Replace OCV. 
   2. OK: Go to next step. 
3. Check voltage between terminals OC1 (or 2) + and OC1 (or 2) - of ECM connector. 

   Reference: INSPECTION USING OSCILLOSCOPE 

   Turn the ignition switch ON, and check the waveform between terminals OC1 (or 2) + and OC1 (or 2) - of the ECM connector.

   HINT:

   The correct waveform is as shown.

   Fig 2: Inspecting Using Oscilloscope

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. NG: Check and replace ECM (See  PROCEDURE  ).  
   2. OK: Go to next step. 
4. Check for open and short in harness and connector between OCV and ECM (See  PROCEDURE  ).  
   1. NG: Repair or replace 
   2. OK: Check for intermittent problems (See  PRE-CHECK  ).  

OBD II scan tool (excluding hand-held tester): 

1. Check operation of OCV. 

   PREPARATION: 

   1. Start the engine and warmed it up.
   2. Disconnect the OCV connector.
   3. Apply battery positive voltage between terminals of the OCV.

   CHECK: 

   Check the engine speed.

   OK: 

   Rough idle or engine stalled 

   Fig 3: Checking Operation Of OCV

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. NG: Replace OCV. 
   2. OK: Go to next step. 
2. Check voltage between terminals OC1 (or 2) + and OC1 (or 2) - of ECM connector. 

   Reference: INSPECTION USING OSCILLOSCOPE 

   Turn the ignition switch ON, and check the waveform between terminals OC1 (or 2) + and OC (or 2) - of the ECM connector.

   HINT:

   The correct waveform is as shown.

   Fig 4: Checking Oscilloscope Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. NG: Check and replace ECM (See  PROCEDURE  ).  
   2. OK: Go to next step. 
3. Check for open and short in harness and connector between OCV and ECM (See  PROCEDURE  ).  
   1. NG: Repair or replace. 
   2. OK: Check for intermittent problems (See  PRE-CHECK  ).