CAN junction connector SUZUKI SWIFT 2007 2.G Service User Guide
[x] Cancel search | Manufacturer: SUZUKI, Model Year: 2007, Model line: SWIFT, Model: SUZUKI SWIFT 2007 2.GPages: 1496, PDF Size: 34.44 MB
Page 597 of 1496

Downloaded from www.Manualslib.com manuals search engine Electronic Stability Program: 4F-23
ABS Warning Lamp Does Not Come ON at Ignition Switch ONS7RS0B4604048
Wiring Diagram4
Check ESP ® control module power supply circuit
1) Turn ignition switch to OFF position.
2) Check for proper connection to ESP ® control module
connector at terminals “E85-1” and “E85-32”.
3) If OK, then turn ignition switch to ON position and measure voltage between each terminal of “E85-1”,
“E85-32” and vehicle body ground.
Are they 10 – 14 V? Go to Step 5. “WHT/BLU” and/or
“WHT/RED” circuit
open.
5 Check ESP ® control module ground circuit
1) Turn ignition switch to OFF and measure resistance between each terminal of “E85-16”, “E85-47” and vehicle
body ground.
Is resistance less than 2
Ω? Go to Step 6.
Ground circuit for ESP®
control module open or
high resistance.
6 CAN communication circuit check
1) Check CAN communication circuit between combination
meter and ESP ® control module referring to “DTC
U1073: Control Module Communication Bus Off”.
Is CAN communication circuit in good condition? Substitute a known-
good combination meter
and recheck. If warning
lamp remains ON,
substitute a known-
good ESP
® hydraulic
unit / control module
assembly and recheck. Repair or replace.
Step
Action YesNo
[A]
E85
161
15
2
3
4
5
6
7
8
9
10
11
12
13
14
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
3233
34
35
36
37
38
39
40
41
42
43
44
45
46
47
WHTGRN
3
E85-13
E85-44REDWHT6 5E46-1E46-2
4 10
6
E85-16
E85-47BLKBLK
8
9
BLK/ORN
REDWHT
REDWHT
G37-4G37-2
G28-10G28-8
G28-16
12V
12VE85-32E85-1
E85-35
WHT/REDWHT/BLU
GRN/ORN
6
2
1
7 1112[B]
G37
E46124
53
67
891011121314124
53
67
891011
1213141516171819202122
[C] G28
12345678910111213141516
17181920212223242526272829303132
G28-31
RED/BLK
I6RS0B460010-01
[A]: ESP ® control module connector (viewed
from terminal side) 3. Ignition switch 8. ABS warning lamp
[B]: BCM connector (viewed from harness side) 4. Junction block assembly 9. Lamp driver module
[C]: Combination meter connector (viewed from harness side) 5. BCM (included in junction block
assembly) 10. ESP
® hydraulic unit / control module
assembly
1. Battery 6. CAN driver11. Junction connector
2. Main fuse box 7. Combination meter12. To steering angle sensor
Page 598 of 1496

Downloaded from www.Manualslib.com manuals search engine 4F-24 Electronic Stability Program:
Circuit Description
Operation (ON/OFF) of ABS warning lamp is controlled by ESP® control module through lamp driver module in
combination meter.
If antilock brake system is in good condition, ESP ® control module turns ABS warning lamp ON at the ignition switch
ON, keeps it ON for 2 seconds and then turns it OFF. If an abnormality in the system is detected, ABS warning lamp is
turned ON continuously by ESP ® control module. Also, it is turned ON continuously by lamp driver module when the
connector of ESP ® control module is disconnected.
Troubleshooting
Refer to “Troubleshooting” under “ESP ® Warning Lamp Does Not Come ON at Ignition Switch ON”.
ABS Warning Lamp Comes ON SteadyS7RS0B4604049
Wiring Diagram
Refer to “Wiring Diagram” under “ABS Warning Lamp Does Not Come ON at Ignition Switch ON”.
Circuit Description
Refer to “Circuit Description” u nder “ABS Warning Lamp Does Not Co me ON at Ignition Switch ON”.
Troubleshooting
Refer to “Troubleshooting” under “ESP ® Warning Lamp Comes ON Steady”.
EBD Warning Lamp (Brake Warning Lamp) Comes ON SteadyS7RS0B4604050
Wiring Diagram
[A]
E85
161
15
2
3
4
5
6
7
8
9
10
11
12
13
14
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
3233
34
35
36
37
38
39
40
41
42
43
44
45
46
47WHTGRN
3
E85-13
E85-44REDWHT8 5E46-1E46-2
4
13
8
E85-16
E85-47BLKBLK
1110
12
BLK/ORN
REDWHT
REDWHT
G37-4G37-2
G28-10G28-8
G28-16
12V
12VE85-32E85-1
E85-35
WHT/REDWHT/BLU
GRN/ORN
8
2
1
9 1415
[B]
G37
E46
124
53
67
891011121314124
53
67
891011
1213141516171819202122
[C] G28
12345678910111213141516
17181920212223242526272829303132
12V
12V
6
7E46-5
L01-6
RED/BLK
RED/BLK
G28-31
RED/BLK
I6RS0B460011-01
[A]: ESP ® control module connector (viewed from terminal side) 4. Junction block assembly 10. EBD warning lamp (brake warning lamp)
[B]: BCM connector (viewed from harness side) 5. BCM (included in junction block
assembly) 11. ABS warning lamp
[C]: Combination meter connector (viewed from harness side) 6. Brake fluid level switch 12. Lamp driver module 1. Battery 7. Parking brake switch 13. ESP ® hydraulic unit / control module
assembly
2. Main fuse box 8. CAN driver 14. Junction connector
3. Ignition switch 9. Combination meter 15. To steering angle sensor
Page 600 of 1496
![SUZUKI SWIFT 2007 2.G Service User Guide Downloaded from www.Manualslib.com manuals search engine 4F-26 Electronic Stability Program:
Serial Data Link Circuit CheckS7RS0B4604012
Wiring Diagram
Inspection
[A]E85
161
15
2
3
4
5
6
7
8
9
10
11
SUZUKI SWIFT 2007 2.G Service User Guide Downloaded from www.Manualslib.com manuals search engine 4F-26 Electronic Stability Program:
Serial Data Link Circuit CheckS7RS0B4604012
Wiring Diagram
Inspection
[A]E85
161
15
2
3
4
5
6
7
8
9
10
11](/img/20/7607/w960_7607-599.png)
Downloaded from www.Manualslib.com manuals search engine 4F-26 Electronic Stability Program:
Serial Data Link Circuit CheckS7RS0B4604012
Wiring Diagram
Inspection
[A]E85
161
15
2
3
4
5
6
7
8
9
10
11
12
13
14
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
3233
34
35
36
37
38
39
40
41
42
43
44
45
46
47WHTGRN
3
E85-13REDWHT6 5E46-1E46-2
4
10
6
E85-16
E85-47BLKBLK
8
9
BLK/ORN
REDWHT
REDWHT
G37-4G37-2
G28-10G28-8
G28-16
G28-31
12V
12VE85-32E85-1
E85-35
WHT/REDWHT/BLU
GRN/ORN
6
2
1
7 1415 [B]
G37
E46
124
53
67
891011121314124
53
67
891011
1213141516171819202122
[C] G28
12345678910111213141516
17181920212223242526272829303132
12V
11
PPL/WHT
PPL/WHT
E85-33
E85-44
12
13
WHTWHT/REDB
G G1
RED/BLK
I6RS0B460012-01
[A]: ESP
® control module connector (viewed
from terminal side) 4. Junction block assembly 10. ESP
® hydraulic unit / control module assembly
[B]: BCM connector (viewed from harness side) 5. BCM (included in junction block
assembly) 11. Data link connector (DLC)
[C]: Combination meter connector (viewed from harness side) 6. CAN driver 12. To SDM
1. Battery 7. Combination meter 13. To ECM and P/S control module
2. Main fuse box 8. ESP ® warning lamp 14. Junction connector
3. Ignition switch 9. Lamp driver module 15. To steering angle sensor
Step Action YesNo
1 Check ESP ® warning lamp
1) Turn ignition switch to ON position.
Does ESP
® warning lamp come ON? Go to Step 2. Go to Step 6.
2 Check fuse
1) Turn ignition switch to OFF position.
Are main fuses for good condition? Go to Step 3. Replace fuse and check
for short.
3 Check ESP ® control module power supply circuit
1) Disconnect ESP ® control module connector.
2) Check for proper connection to ESP ® control module
connector at terminal “E85-35”.
3) If OK, then turn ignition switch to ON position and measure voltage between terminal “E85-35” and vehicle
body ground.
Is it 10 – 14 V? Go to Step 4.
“GRN/ORN” wire circuit
open.
Page 610 of 1496

Downloaded from www.Manualslib.com manuals search engine 4F-36 Electronic Stability Program:
DTC C1034: Yaw Rate / G Sensor Assembly Power Supply FailureS7RS0B4604032
Wiring Diagram
DTC Detecting Condition and Trouble Area
DTC Troubleshooting
[A]E85
161
15
2
3
4
5
6
7
8
9
10
11
12
13
14
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
3233
34
35
36
37
38
39
40
41
42
43
44
45
46
47 [B]
E84
3
521
46
1
E85-16
E85-47
12V
12VE85-32
E85-1
E85-35GRNWHT
WHT/RED
WHT/BLU
E85-29E85-25
E85-37
E85-31
E84-3
E84-5
RED/BLK
BLK
BLK
WHT/BLKE84-2E84-1 12V
GRN/BLK
BLU/RED
23
5
6 4
7
6
GRN/ORN
I7RS0B460009-01
[A]: ESP ® control module connector (viewed from terminal side ) 2. Main fuse box 5. Yaw rate / G sensor assembly
[B]: Yaw rate / G sensor assembly connector (viewed from harness side) 3. Ignition switch 6. CAN driver
1. Battery 4. Junction block assembly 7. ESP ® hydraulic unit / control module assembly
DTC Detecting Condition Trouble Area
• Power supply voltage of yaw rate / G sensor assembly is too high when ignition switch OFF.
• Power supply voltage of yaw rate / G sensor assembly is too low when ignition switch ON. • Yaw rate / G sensor assembly power supply circuit
• ESP
® control module power supply circuit
• Yaw rate / G sensor assembly
• ESP ® control module
Step Action YesNo
1 Was “Electronic Stability Pr ogram Check” performed? Go to Step 2.Go to “Electronic
Stability Program
System Check”.
2 Check yaw rate / G sensor assembly ground circuit
1) Turn ignition switch to OFF position.
2) Disconnect yaw rate / G se nsor assembly connector.
3) Check for proper connection to yaw rate / G sensor assembly connector terminals at “E84-3” and “E84-5”.
4) If OK, then measure voltage between connector terminal “E84-3” and vehicle body ground.
Is it 0 V? Go to Step 3.
Go to Step 4.
3 Check yaw rate / G sensor assembly power supply
circuit
1) Measure voltage between connector terminal “E84-3”
and “E84-5” with ignition switch turned ON.
Is it 10 – 14 V? Substitute a known-
good yaw rate / G
sensor assembly and
recheck.
Go to Step 4.
Page 611 of 1496

Downloaded from www.Manualslib.com manuals search engine Electronic Stability Program: 4F-37
DTC C1037: Steering Angle Sensor Power Supply FailureS7RS0B4604033
Wiring Diagram
DTC Detecting Condition and Trouble Area4
Check yaw rate / G sensor assembly power supply
circuit
1) Turn ignition switch to OFF position.
2) Disconnect ESP ® control module connector.
3) Check for proper connection to ESP ® control module
connector terminals at “E85-31” and “E85-37”.
4) If OK, then measure voltage between connector terminal “E85-37” and vehicle body ground.
Is it 0 V? Go to Step 5. “BLU/RED” wire circuit
is shorted to power
circuit.
5 Check yaw rate / G sensor assembly power supply
circuit
1) Measure resistance between the following points.
• Between terminal “E85-37” of module connector and terminal “E84-3” of sensor terminal.
• Between terminal “E85-31” of module connector and terminal “E84-5” of sensor terminal.
Are resistance less than 2
Ω? Substitute a known-
good ESP
® hydraulic
unit / control module
assembly recheck. “BLU/RED” and/or
“GRN/BLK” wire circuit
open or high resistance.
Step
Action YesNo
[A]
E85
161
15
2
3
4
5
6
7
8
9
10
11
12
13
14
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
3233
34
35
36
37
38
39
40
41
42
43
44
45
46
47
[C] G37
E46
124
53
67
891011121314124
53
67
891011
1213141516171819202122
WHTGRN
3
E85-13
E85-44REDWHT65E46-1E46-2
4 8
6
BLK/ORN
REDWHT
REDWHT
G37-4G37-2
G50-10G50-9
G50-2
6
2
1
7 910
G50-1
G50-3
GRN/ORN
WHT/RED
WHT
[B]
G50
109 321
I6RS0B460020-01
[A]: ESP® control module connector (viewed from
terminal side) 3. Ignition switch 8. ESP
® hydraulic unit control module assembly
[B]: Steering angle sensor connector (viewed from harness side) 4. Junction block assembly 9. Junction connector
[C]: BCM connector (viewed from harnes s side) 5. BCM (included in junction block
assembly) 10. To Combination meter and keyless start control
module
1. Battery 6. CAN driver
2. Main fuse box 7. Steering angle sensor
DTC Detecting Condition Trouble Area
Power supply voltage to steering angle sensor is to o low. • Steering angle sensor power supply circuit
• Steering angle sensor
• ESP® control module
Page 623 of 1496

Downloaded from www.Manualslib.com manuals search engine Electronic Stability Program: 4F-49
DTC U1073: Control Module Communication Bus OffS7RS0B4604057
Wiring Diagram
DTC Detecting Condition and Trouble Area
E85-13E85-44
E46-2E46-1
G37-4G37-2
E85-46E85-42
E23-3E23-18
G50-9G50-10
G28-8G28-10
G28-9G28-7
G42-19G42-18
REDWHT
WHTRED
WHTRED
REDWHT
REDWHT
WHTRED
REDWHT
REDWHT
REDWHT
[A]
21
E2334
1819
5671011
17
20
47 46
495051
2122
52 16
25 9
24
14
29
5557 54 53
59
60 5826
27
28
15
30
56 4832 31343536374042 39 38
44
45 43 41 33
1213
238
G42[F]
1234567891011
141516
36 34 33 32 31 30 29 24 23
37
181920
[B]
E85
161
15
2
3
4
5
6
7
8
9
10
11
12
13
14
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
3233
34
35
36
37
38
39
40
41
42
43
44
45
46
47 [C]
G37
E46
124
53
67
891011121314124
53
67
891011
1213141516171819202122
[E] G28
12345678910111213141516
17181920212223242526272829303132
[D] G50
109 321
4
5
7 1
2
3
6
I7RS0B460011-02
[A]: ECM connector (viewed from harness side) [F]: Keyless start control module
connector (viewed from
harness side) 5. Combination meter
[B]: ESP ® control module connector (viewed from
terminal side) 1. ECM
6. Keyless start control module (if equipped)
[C]: BCM connector (viewed from harness side) 2. ESP® hydraulic unit / control
module assembly 7. Junction connector
[D]: Steering angle sensor connector (viewed from harness side) 3. BCM
[E]: Combination meter connector (viewed from harness side) 4. Steering angle sensor
DTC Detecting Condition
Trouble Area
Transmission error that is inconsistent between
transmission data and transmission monitor (CAN bus
monitor) data is detected more than 7 times continuously. • CAN communication circuit
•ECM
• ESP
® control module
•BCM
• Steering angle sensor
• Combination meter
• Keyless start control module (if equipped)
Page 908 of 1496

Downloaded from www.Manualslib.com manuals search engine 6C-26 Power Assisted Steering System:
DTC C1121 / C1123 / C1124: VSS Circuit FailureS7RS0B6304017
DTC C1121: No Vehicle Speed Signal (60 Seconds or More)
DTC C1123: No Vehicle Speed Signal (30 Seconds or More)
DTC C1124: Vehicle Speed Performance (Impossible Deceleration)
Wiring Diagram
DTC Detecting Condition and Trouble Area
M
BRNRED/
BLU
BLK
RED
E52-14
E52-12
E23-4
E23-26
E23-25 E51-1
E51-2
[A ]
12
3
4 5 67
89
11
10
12 13
141516
17 18 19 20
5V
PPL
E52-4
8
5
12V
E49-2BLK
12V
12V
6REDRED/ BLKWHT
7WHTWHT/BLKWHTBLK BLK
111
2
[B ]
9
LT GRN
/BLKE52-1 E49-1
GRNGRNWHTBLK
WHY
10
3
4
4
4
4
1 2
12
I7RS0B630009-01
[A]: Connector “E52” (viewed from harness side)
4. Fuse9. ABS/ESP® control module
[B]: Connector “E49” (viewed from harness si de)5. ECM 10. Individual circuit fuse box No.1
1. Main fuse box 6. Left-front wheel speed sensor11. Vehicle speed signal circuit
2. Ignition switch 7. Right-front wheel speed sensor 12. Engine speed signal circuit
3. Junction block assembly 8. P/S control module
DTC detecting condition Trouble area
DTC C1121:
Vehicle speed signal is 0 km/h even though engine speed
is more than 4000 rpm for more than 60 seconds
continuously (before elapse of 5 min from engine start) or
vehicle speed signal is 0 km/h even though engine speed
is more than 2500 rpm for more than 60 seconds
continuously (after elapse of 5 min for engine start).
(1 driving cycle detection logic but MIL does not light up)
DTC C1123:
Vehicle speed signal is 0 km/h with continuously more
than 3 driving cycles even though engine speed is more
than 4000 rpm for more than 30 seconds continuously
(before elapse of 5 min from engine start) or vehicle speed
signal is 0 km/h with continuously more than 3 driving
cycles even though engine speed is more than 2500 rpm
for more than 30 seconds continuously (after elapse of 5
min for engine start).
(3 driving cycle detection logic)
DTC C1124:
Vehicle speed signal is less than 5 km/h for more than 5
seconds continuously with more than specified
deceleration speed (–20 m/s
2) from over 20 km/h.
(1 driving cycle detection logic but MIL does not light up) • Vehicle speed signal circuit
• Wheel speed sensor
•ECM
• P/S control module
• ABS/ESP®
control module
• CAN communication circuit
Page 1010 of 1496

Downloaded from www.Manualslib.com manuals search engine 7B-62 Air Conditioning System: Automatic Type
DTC B1541: HVAC Control Module Back-Up Power Supply MalfunctionS7RS0B7224017
Wiring Diagram
DTC Detecting Condition and Trouble Area
DTC Troubleshooting11
Position sensor circuit check
1) Check air flow control actuator position sensor circuit
referring to Step 1 to Step 5 and Step 10 to Step 11 of
“DTC B1512: Air flow Control Actuator (Position Sensor)
and/or Its Circuit Malfunction”.
Is it in good condition? Go to Step 12. Repair circuit.
12 Air flow control actuator check
1) Check air flow control actuator referring to “Air Flow
Control Actuator Inspection”.
Is it in good condition? HVAC control module
faulty.
Air flow control actuator
faulty.
Step Action Yes No
WHT/RED
2 17812910
65 431516 14 13 12 11
G52
789101920121112
65 431718 16 15 14 13
G51
3
G52-16
I5RS0A722015-01
1. HVAC control module
2. Junction block assembly 3. Circuit fuse
DTC Detecting Condition Trouble Area
Back-up power supply voltage is lo wer than specified value continuously. • Battery voltage supply circuit
• HVAC control module
StepAction YesNo
1 DTC check
1) Turn ON ignition switch for 20 sec. or more.
2) Ignition switch turned OF F and connect scan tool to
DLC.
3) Turn ON ignition switch and check DTC.
Is there DTC B1541? Go to Step 2.
Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
2 Battery voltage supply circuit check
1) Disconnect connector from HVAC control module with
ignition switch turned OFF.
2) Check for proper connection to HVAC control module connector at “G52-16” terminal.
3) If OK, measure voltage between “G52-16” terminal of HVAC control module connector and vehicle body
ground.
Is voltage 10 – 14 V? HVAC control module
faulty.
Circuit fuse blown and/
or “WHT/RED” wire
circuit open or short.
Page 1012 of 1496

Downloaded from www.Manualslib.com manuals search engine 7B-64 Air Conditioning System: Automatic Type
DTC Detecting Condition and Trouble Area
DTC Troubleshooting
DTC B1552: Serial Communication Signal MalfunctionS7RS0B7224020
DTC Detecting Condition and Trouble AreaDTC detecting condition Trouble area
Serial communication signal is higher than or lower than specified value for
specified time continuously. • Serial communication line of BCM
• BCM (included in junction block
assembly)
• Information display
• HVAC control module
Step Action YesNo
1 DTC check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Disconnect connector from information display.
3) Turn ignition switch ON and check DTC.
Is there DTC B1551? Go to Step 2.
Information display
faulty.
2 Wire harness check
1) Disconnect connectors from BCM and HVAC control
module.
2) Measure resistance between “G37-11” terminal of BCM connector and “G51-7” terminal of HVAC control module
connector.
Is resistance below 5
Ω? Go to Step 3. “YEL” wire open or high
resistance circuit.
3 Wire harness check
1) Measure resistance between “G51-7” terminal of HVAC
control module connector and vehicle body ground.
Is resistance infinity? Go to Step 4. “YEL” wire shorted to
ground circuit.
4 Wire harness check
1) Measure voltage between “G51-7” terminal of HVAC
control module connector and vehicle body ground with
ignition switch turned ON.
Is voltage 0 V? Go to Step 5. “YEL” wire shorted to
other circuit.
5 Serial communication signal check
1) Connect connectors to BCM and HVAC control module.
2) Using oscilloscope, check that serial communication
signal is outputted referring to “Reference waveform
No.8” of “Inspection of BCM and its Circuits in Section
10B”.
Is serial communication signal outputted at “G37-11”
terminal of BCM connector? HVAC control module
faulty.
BCM (included in
junction block
assembly) faulty.
DTC detecting condition
Trouble area
Data received by HVAC control module from BCM is erroneous continuously. • BCM (included in junction block assembly)
• HVAC control module
Page 1013 of 1496

Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Automatic Type 7B-65
DTC Troubleshooting
DTC B1553: CAN Communication Signal MalfunctionS7RS0B7224021
DTC Detecting Condition and Trouble Area
DTC Troubleshooting
DTC B1557: Vehicle Speed Sensor Signal MalfunctionS7RS0B7224022
DTC Detecting Condition and Trouble Area
DTC TroubleshootingStep Action Yes No
1 Serial communication signal data check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Start engine and select “DATA LIST” mode on scan tool.
3) Check “Refrigerant Pressure”, “Vehicle Speed”, “Coolant Temp” and “Outside Air Temp” varies displayed on scan
tool.
Is displayed each va ries described varies in “Scan Tool
Data”? Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
Go to Step 2.
2 Serial communication signal check
1) Connect connectors to BCM and HVAC control module.
2) Using oscilloscope, check that serial communication
signal is outputted referring to “Reference waveform
No.8” of “Inspection of BCM and its Circuits in Section
10B”.
Is serial communication signal outputted at “G37-11”
terminal of BCM connector? HVAC control module
faulty.
BCM (included in
junction block
assembly) faulty.
DTC detecting condition
Trouble area
HVAC control module receives error code fr om BCM continuously.• CAN communication circuit
• BCM (included in junction block assembly)
•ECM
• HVAC control module
Step Action YesNo
1 DTC check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Check ECM and BCM for DTC.
Is there DTC(s)? Go to applicable DTC
diag. flow.
Substitute a known-
good HVAC control
module and recheck.
DTC detecting condition
Trouble area
HVAC control module receives error code from BCM continuously. • VSS circuit
• VSS
• HVAC control module
Step Action YesNo
1 DTC check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Check ECM for DTC.
Is there DTC P0500? Go to “DTC P0480: Fan
1 (Radiator Cooling
Fan) Control Circuit in
Section 1A”.
Substitute a known-
good HVAC control
module and recheck.