Caution / Notice / Hint

HINT: 

• In contrast to normal malfunction diagnosis for components, circuits and systems, DTCs P1603 and P1605 are used to determine the malfunctioning area from the problem symptoms and freeze frame data when the user mentions problems such as engine stall.

  As these DTCs can be stored as a result of certain user actions, even if these DTCs are output, if the customer makes no mention of problems, clear these DTCs without performing any troubleshooting and return the vehicle to the customer.

• If any other DTCs are output, perform troubleshooting for those DTCs first.
• Use any information from the customer problem analysis about the condition of the vehicle at the time when the problem occurred (how the engine stopped, conditions when the engine was restarted, etc.) as a reference.

  Symptom	Suspected Area
  Engine vibration occurs and engine stops	Air-fuel ratio abnormal
  Engine stops with no engine vibration	Ignition system, injection stoppage, high load from external parts
  Engine can be started with accelerator pedal depressed	Insufficient air volume
  Rough idling after engine started	Air-fuel ratio abnormal, abnormal combustion

• Read freeze frame data using the Techstream. Freeze frame data records engine conditions when a malfunction occurs. This information can be useful when troubleshooting.
• When confirming the freeze frame data, be sure to check all 5 sets of freeze frame data (Refer to FREEZE FRAME DATA [12/2015 - 08/2016] ).
• When DTC P1603 (Engine Stall History) is stored, DTC P1605 (Rough Idling) is also stored. When confirming freeze frame data, check DTC P1605. The ECM stores DTC P1605 first. Therefore, 5 sets of freeze frame data can be confirmed through DTC P1605, enabling the technician to obtain more information.
• When confirming freeze frame data, if there are multiple items related to the cause of the malfunction, perform troubleshooting for all related items.
• Try to operate the vehicle under the conditions recorded in the freeze frame data which were present when the malfunction occurred. Confirm the data at this time and the data when the engine is idling (engine warmed up, no load, and shift lever in D or N) and compare these data with the freeze frame data.
• Inspections take into account the fact that the malfunction may not have reoccurred and place emphasis on checking the vehicle conditions present at the time when the malfunction occurred.
• When performing inspections, jiggle the relevant wire harnesses and connectors in an attempt to reproduce malfunctions that do not always occur.

Inspection flow

Using freeze frame data, narrow down the parts to be inspected according to the vehicle conditions at the time when the malfunction occurred.

P1603: 

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1: 

• If the engine stalled when the intake air volume was low (during idling or deceleration), there may be a decrease in torque due to an incorrect air fuel ratio, etc.
• If the engine stalled when the intake air volume was high (during driving or acceleration), there may be a major malfunction such as continuous misfire due to ignition stoppage, fuel injection stoppage, etc. and the torque drops to zero.

2: 

• If the engine speed decreased slowly, there may have been a decrease in torque due to an air fuel ratio that was incorrect (by approximately 20 to 30%), etc.
• If the engine speed decreased rapidly, there may have been a malfunction such as when the engine misfires almost continuously due to ignition stoppage, fuel injection stoppage, etc., or when the external load increases due to an external part malfunctioning.

3: 

• If the air fuel ratio is abnormal, there may have been an intake air leak, sensor malfunction, or fuel supply problem.
• If the air fuel ratio was normal, the air volume may have been insufficient or the ignition timing may have been incorrect.

P1603 inspection flow: Narrow down the parts to be inspected according to the vehicle conditions at the time when the malfunction occurred (freeze frame data).

P1605: 

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1: 

• If the engine speed decreased slowly, there may have been a decrease in torque due to an air fuel ratio that was incorrect (by approximately 20 to 30%), etc.
• If the engine speed decreased rapidly, there may have been a malfunction such as when the engine misfires almost continuously due to ignition stoppage, fuel injection stoppage, etc., or when the external load increases due to an external part malfunctioning.

2: 

• If the air fuel ratio is abnormal, there may have been an intake air leak, sensor malfunction, or fuel supply problem.
• If the air fuel ratio was normal, the air volume may have been insufficient or the ignition timing may have been incorrect.

P1605 inspection flow: Narrow down the parts to be inspected according to the vehicle conditions at the time when the malfunction occurred (freeze frame data).