Dtc B1551: Serial Communication Circuit Malfunction - Suzuki SX4 Service Manual
Hide thumbs
Also See for SX4:
- Owner's manual (47 pages) ,
- Owner's manual (278 pages) ,
- Owner's manual (16 pages)
Table of Contents
Advertisement
7B-68 Air Conditioning System: Automatic Type
DTC B1551: Serial Communication Circuit Malfunction
Wiring Diagram
[B]: Back-up power supply circuit
[S]: Serial communication circuit
DTC Detecting Condition and Trouble Area
Serial communication signal is higher than or lower than specified value for
specified time continuously.
DTC Troubleshooting
Step
1
Was "Air Conditioning System Check" performed?
2
Back-up power supply circuit fuse check
1) Check back-up power supply circuit fuse for blowing.
Is fuse(s) blown?
3
Wire harness check
1) Turn ignition switch to OFF position.
2) Disconnect connectors from BCM, information display
and HVAC control module.
3) Check for proper connection to serial communication
circuit terminal of BCM, information display and HVAC
control module connectors.
4) If OK, check that serial communication circuit is as
follows.
• Wiring harness resistance of serial communication
circuit is less than 3 Ω
• Insulation resistance between serial communication
circuit terminal and vehicle body ground is Infinity
• Circuit voltage of serial communication circuit is 0 - 1
V with ignition switch turned ON
Are they in good condition?
4
[B]
4
WHT/RED
WHT
14
13
12
11
10
9
30
29
28
27
26
25
DTC detecting condition
Action
1
12V
G20-13
YEL
G20-7
5V
12V
G20
8
7
6
5
24
23
22
21
20
19
1. HVAC control module
2. BCM
Go to Step 2.
Replace blown fuse and
check for short in back-
up power supply circuit.
Go to Step 4.
3
2
[S]
4
3
2
1
18
17
16
15
3. Information display
4. Circuit fuse
Trouble area
• Back-up power supply circuit
• Serial communication circuit
• BCM
• Information display
• HVAC control module
Yes
Go to "Air Conditioning
System Check:
Automatic Type".
Go to Step 3.
Serial communication
circuit is open, short or
high resistance.
S7RW0A7224020
I7RW01722012-02
No
Advertisement
Chapters
Table of Contents
Troubleshooting
Need help?
Do you have a question about the SX4 and is the answer not in the manual?
Questions and answers
Adjust throttle motor
The idle speed on a Suzuki SX4 should be controlled by the Idle Air Control Valve (IACV) rather than adjusting the idle screw on the throttle body, as the screw is factory set. Before using compressed air in the idle-air-bypass passages, the IACV should be removed to prevent damage to its delicate mechanism. If there is an issue with idle speed, checking the IACV function and referring to the SX4 service manual is recommended.
This answer is automatically generated
I have an issue of crank but not starting When I scan it brought this codeU0100 Which means no communication thou crank sensor wire was cut off but it was fix back What could be wrong and what could be the solution,
increasing revs when changing gears
The Suzuki SX4 may have increasing revs when changing gears due to its drive-by-wire system and the difference in final drive ratios between the manual (4.41) and automatic (2.81) transmissions. This difference causes high cruising RPMs in the manual version and sluggishness in the automatic. Additionally, if the revs climb while going uphill, it may be due to the transmission downshifting or kicking out of overdrive. Other possible causes include low transmission fluid, abuse, or a faulty transmission design.
This answer is automatically generated
My heater stopped working the blower **** is good, control unit ?
Possible issues with the heater in a Suzuki SX4 if the blower is working but the heater is not include:
1. Incorrect Temperature Output
- Temperature control cable broken or bent (non-A/C and manual A/C) → Check the temperature control cable.
- Temperature selector faulty (non-A/C and manual A/C) → Check the temperature selector.
- Incorrect installation of the temperature control cable (non-A/C and manual A/C) → Check and adjust the position as necessary.
- Temperature control door assembly broken → Repair the temperature control door assembly.
- Air ducts clogged → Repair air ducts.
- Heater core leaked or clogged → Replace the heater core.
- Heater hoses leaked or clogged → Replace heater hoses.
- Thermostat faulty → Check the thermostat.
- Temperature control actuator faulty (auto A/C) → Check the temperature control actuator.
- HVAC control module faulty (auto A/C) → Check the HVAC control module.
- Wiring or grounding faulty (auto A/C) → Repair as necessary.
2. Other Possible Causes
- Air flow control cable broken or bent → Check the air flow control cable.
Checking and addressing these components should help identify and resolve the heater issue.
This answer is automatically generated