- Quick heater assembly malfunction
- Air conditioning amplifier assembly malfunction
- PTC HTR relay malfunction
- Harness or connector
| Last Modified: 05-13-2024 | 6.11:8.1.0 | Doc ID: RM100000001H986 |
| Model Year Start: 2020 | Model: Corolla | Prod Date Range: [01/2019 - 09/2022] |
| Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): PTC Heater Circuit; 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022] | ||
|
PTC Heater Circuit |
DESCRIPTION
The air conditioning amplifier assembly sends operation signals to the PTC HTR relays when quick heater assembly operation conditions are met. Based on the signals from the air conditioning amplifier assembly, the PTC HTR relays turn on, and power is supplied to the quick heater assembly installed in the air conditioning radiator assembly.
|
Symptom |
Factor |
|---|---|
|
Heating performance is poor when it is cold. |
|
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Inspect the fuses for circuits related to this system before performing the following procedure.
PROCEDURE
|
1. |
INSPECT PTC HTR RELAY |
(a) Inspect the PTC HTR relays.
Click here
![2020 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - ]; HEATING / AIR CONDITIONING: RELAY: ON-VEHICLE INSPECTION](/t3Portal/stylegraphics/info.gif)
| NG |
|
REPLACE PTC HTR RELAY |
|
|
2. |
CHECK HARNESS AND CONNECTOR (POWER SOURCE - PTC HTR RELAY) |
(a) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
PTC HTR NO. 1
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
3 (PTC HTR NO. 1 relay) - Body ground |
Power switch off |
11 to 14 V |
|
2 (PTC HTR NO. 1 relay) - Body ground |
Power switch off |
Below 1 V |
|
2 (PTC HTR NO. 1 relay) - Body ground |
Power switch on (IG) |
11 to 14 V |
Standard Voltage:
PTC HTR NO. 2
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
3 (PTC HTR NO. 2 relay) - Body ground |
Power switch off |
11 to 14 V |
|
1 (PTC HTR NO. 2 relay) - Body ground |
Power switch off |
Below 1 V |
|
1 (PTC HTR NO. 2 relay) - Body ground |
Power switch on (IG) |
11 to 14 V |
Standard Voltage:
PTC HTR NO. 3
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
3 (PTC HTR NO. 3 relay) - Body ground |
Power switch off |
11 to 14 V |
|
1 (PTC HTR NO. 3 relay) - Body ground |
Power switch off |
Below 1 V |
|
1 (PTC HTR NO. 3 relay) - Body ground |
Power switch on (IG) |
11 to 14 V |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
3. |
CHECK HARNESS AND CONNECTOR (PTC HTR RELAY - AIR CONDITIONING AMPLIFIER ASSEMBLY) |
(a) Disconnect the I48 and I49 air conditioning amplifier assembly connectors.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
PTC HTR NO. 1
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
1 (PTC HTR NO. 1 relay) - I49-23 (PTC1) |
Always |
Below 1 Ω |
|
1 (PTC HTR NO. 1 relay) or I49-23 (PTC1) - Body ground |
Always |
10 kΩ or higher |
Standard Resistance:
PTC HTR NO. 2
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
2 (PTC HTR NO. 2 relay) - I48-16 (PTC2) |
Always |
Below 1 Ω |
|
2 (PTC HTR NO. 2 relay) or I48-16 (PTC2) - Body ground |
Always |
10 kΩ or higher |
Standard Resistance:
PTC HTR NO. 3
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
2 (PTC HTR NO. 3 relay) - I48-17 (PTC3) |
Always |
Below 1 Ω |
|
2 (PTC HTR NO. 3 relay) or I48-17 (PTC3) - Body ground |
Always |
10 kΩ or higher |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
4. |
CHECK HARNESS AND CONNECTOR (PTC HTR RELAY - QUICK HEATER ASSEMBLY AND BODY GROUND) |
(a) Disconnect the J1 and J2 quick heater assembly connectors.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
PTC HTR NO. 1
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
5 (PTC HTR NO. 1 relay) - J1-3 (B) |
Always |
Below 1 Ω |
|
5 (PTC HTR NO. 1 relay) or J1-3 (B) - Other terminals and body ground |
Always |
10 kΩ or higher |
Standard Resistance:
PTC HTR NO. 2
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
5 (PTC HTR NO. 2 relay) - J1-1 (B) |
Always |
Below 1 Ω |
|
5 (PTC HTR NO. 2 relay) or J1-1 (B) - Other terminals and body ground |
Always |
10 kΩ or higher |
Standard Resistance:
PTC HTR NO. 3
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
5 (PTC HTR NO. 3 relay) - J2-2 (B) |
Always |
Below 1 Ω |
|
5 (PTC HTR NO. 3 relay) or J2-2 (B) - Other terminals and body ground |
Always |
10 kΩ or higher |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
5. |
CHECK HARNESS AND CONNECTOR (QUICK HEATER ASSEMBLY - BODY GROUND) |
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
J1-2 (E) - Body ground |
Always |
Below 1 Ω |
|
J2-1 (E) - Body ground |
Always |
Below 1 Ω |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
6. |
INSPECT QUICK HEATER ASSEMBLY |
(a) Remove the quick heater assembly.
Click here
(b) Inspect the quick heater assembly.
Click here
| OK |
|
| NG |
|
REPLACE QUICK HEATER ASSEMBLY
|
|
|