Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001G70F
Model Year Start: 2020 Model: Corolla Prod Date Range: [01/2019 - 09/2022]
Title: METER / GAUGE / DISPLAY: METER / GAUGE SYSTEM (for HV Model): Operating Light Control Rheostat does not Change Light Brightness; 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]

Operating Light Control Rheostat does not Change Light Brightness

DESCRIPTION

The combination meter assembly receives signals from the light control rheostat to adjust the illumination of the combination meter assembly. The combination meter assembly sets the illumination level based on the user operation of the light control rheostat.

HINT:

The tail cancel switch is built into the light control rheostat. When the light control rheostat is moved to the highest position, the tail cancel switch will turn on and the meter illumination will be set to maximum brightness.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When replacing the combination meter assembly, always replace it with a new one. If a combination meter assembly which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.

PROCEDURE

1.

CHECK SYMPTOMS

(a) Ask the customer about the problem symptoms.

Result

Proceed to

Meter illumination does not change when operating the light control rheostat

A

Tail cancel switch malfunction

B

B

GO TO STEP 5

A

2.

READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Combination Meter / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Combination Meter > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Rheostat value

Light control rheostat input

Min.: 0.00%, Max.: 100.01% or Unset

Increases from 0 to 100 as light control rheostat turned from low to high

"Unset" is displayed when the light control rheostat is moved to the highest position (tail cancel switch is turned on).

Body Electrical > Combination Meter > Data List

Tester Display

Rheostat value

OK:

The value displayed on the Techstream changes according to the actual light control rheostat operation.

OK

REPLACE COMBINATION METER ASSEMBLY 2020 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 03/2019]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [03/2019 - 09/2022]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL

NG

3.

INSPECT LIGHT CONTROL RHEOSTAT

(a) Remove the light control rheostat.

Click here 2019 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [06/2018 -        ]; METER / GAUGE / DISPLAY: LIGHT CONTROL RHEOSTAT: REMOVAL

(b) Inspect the light control rheostat.

Click here 2019 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [06/2018 -        ]; METER / GAUGE / DISPLAY: LIGHT CONTROL RHEOSTAT: INSPECTION

NG

REPLACE LIGHT CONTROL RHEOSTAT

OK

4.

CHECK HARNESS AND CONNECTOR (LIGHT CONTROL RHEOSTAT - COMBINATION METER ASSEMBLY)

(a) Disconnect the I4 combination meter assembly connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

I27-5 (T) - I4-34 (SW1)

Always

Below 1 Ω

I27-4 (RV) - I4-16 (SW2)

Always

Below 1 Ω

I27-2 (E) - I4-11 (SW3)

Always

Below 1 Ω

I27-5 (T) or I4-34 (SW1) - Body ground

Always

10 kΩ or higher

I27-4 (RV) or I4-16 (SW2) - Body ground

Always

10 kΩ or higher

OK

REPLACE COMBINATION METER ASSEMBLY 2020 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 03/2019]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [03/2019 - 09/2022]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.

READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Combination Meter / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Combination Meter > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Meter Day Mode Switch

Tail cancel switch (Light control rheostat)

OFF or ON

OFF: Tail cancel switch off

ON: Tail cancel switch on

When the light control rheostat is moved to the highest position, the tail cancel switch will turn on.

Body Electrical > Combination Meter > Data List

Tester Display

Meter Day Mode Switch

OK:

Normal conditions listed above are displayed.

OK

REPLACE COMBINATION METER ASSEMBLY 2020 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 03/2019]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [03/2019 - 09/2022]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL

NG

6.

INSPECT LIGHT CONTROL RHEOSTAT

(a) Remove the light control rheostat.

Click here 2019 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [06/2018 -        ]; METER / GAUGE / DISPLAY: LIGHT CONTROL RHEOSTAT: REMOVAL

(b) Inspect the light control rheostat.

Click here 2019 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [06/2018 -        ]; METER / GAUGE / DISPLAY: LIGHT CONTROL RHEOSTAT: INSPECTION

NG

REPLACE LIGHT CONTROL RHEOSTAT

OK

7.

CHECK HARNESS AND CONNECTOR (LIGHT CONTROL RHEOSTAT - COMBINATION METER ASSEMBLY)

(a) Disconnect the I4 combination meter assembly connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

I27-5 (T) - I4-34 (SW1)

Always

Below 1 Ω

I27-3 (TC) - I4-17 (TC)

Always

Below 1 Ω

I27-5 (T) or I4-34 (SW1) - Body ground

Always

10 kΩ or higher

I27-3 (TC) or I4-17 (TC) - Body ground

Always

10 kΩ or higher

OK

REPLACE COMBINATION METER ASSEMBLY 2020 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 03/2019]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [03/2019 - 09/2022]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR