Inspection Procedure

HINT:

• Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

• STP signal conditions can be checked using the intelligent tester.

(a)Connect the intelligent tester to the DLC3.

(b)Turn the ignition switch ON.

(c)Turn the tester ON.

(d)Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / STOP LIGHT SW.

(e)Check the STP signal when the brake pedal is depressed and released.

Brake Pedal Operation

Specified Conditions

Depressed

STP signal ON

Released

STP signal OFF

CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL B VOLTAGE)

Wire Harness Side:

Stop Light Q Switch Connector

(a) Disconnect the A3 stop light switch connector.

(b) Turn the ignition switch ON.

(c) Measure the voltage between the terminals of the A3 stop light switch connector and body ground. Standard voltage

Front View

Tester Connections

Specified Conditions

A3-2 (B) - Body ground

9 to 14 V

A3-3 (B) - Body ground

(d) Reconnect the stop light switch connector.

Go to step 4

INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Remove the stop light switch.

(b) Check the resistance. Standard resistance

Tester Connections

Switch Positions

Specified Conditions

1 - 2

Switch pin not pushed

Below 1 Q

Switch pin pushed

10 kQ or higher

3 - 4

Switch pin not pushed

10 kQ or higher

Switch pin pushed

Below 1 Q

(c) Reinstall the stop light switch.

REPLACE STOP LIGHT SWITCH ASSEMBLY

CHECK ECM (STP AND ST1 - VOLTAGE)

(a) Disconnect the A9 ECM connector.

(b) Turn the ignition switch ON.

(c) Measure the voltage between the terminals ST1- and STP of the A9 ECM connector and body ground. Standard voltage

Tester Connections

Brake Pedal Operations

Specified Conditions

A9-35 (ST1-) - Body ground

Released

9 to 14 V

Depressed

0 to 3 V

A9-36 (STP) - Body ground

Released

0 to 3 V

Depressed

9 to 14 V

(d) Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE ECM

INSPECT FUSE (STOP AND IGN FUSE)

(a) Remove the STOP and IGN fuses from the instrument panel junction block.

(b) Measure the resistance. Standard resistance:

Below 1 Q

(c) Reinstall the STOP and IGN fuses.

CHECK FOR SHORTS IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECKING MONITOR STATUS

The purpose of the monitor result (mode 06) is to allow access to the results of on-board diagnostic monitoring tests of specific components/systems that are not continuously monitored. Examples are catalysts, evaporative emissions (EVAP) and thermostats.

The monitor result allows the OBD II scan tool to display the monitor status, test value, minimum test limit and maximum test limit. These data are displayed after the vehicle has been driven to run the monitor.

When the test value is not between the minimum and maximum test limits, the ECM (PCM) interprets this as a malfunction. If the test value is on the borderline of the test limits, the component is likely to malfunction in the near future.

Perform the following instruction to view the monitor status. Although this instruction refers to the Lexus/Toyota diagnostic tester, it can be checked using a generic OBD II scan tool. Refer to your scan tool operator's manual for specific procedural information.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

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