Hvac Control Description; Sub-Cool A/C System Description - Suzuki SX4 Service Manual
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Also See for SX4:
- Owner's manual (47 pages) ,
- Owner's manual (18 pages) ,
- Owner's manual (16 pages)
Table of Contents
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HVAC Control Description
Temperature Control
HVAC control module calculates the target temperature
control door position based on signals from the
temperature selector, inside air temperature sensor,
outside air temperature sensor and sunload sensor and
controls the temperature control actuator so that the
current position of the temperature control door matches
its target position.
Fan Speed Control
HVAC control module calculates the target blower fan
speed based on signals from the temperature selector,
inside air temperature sensor, outside air temperature
sensor, ECT sensor and sunload sensor, compares it
with the current blower fan speed inputted from the
blower motor controller to control the current blower fan
speed to the target level.
Air Flow Outlet Control
HVAC control module calculates the target temperature
control door position based on signals from the
temperature selector, inside air temperature sensor,
outside air temperature sensor, ECT sensor and sunload
sensor. Using thus obtained target temperature control
door position, it further calculates the target air flow
control door position and controls the air flow control
actuator so that the current air flow control door position
becomes the target position.
Air Intake Position Control
HVAC control module determines the position of the air
intake control door based on signals from the
temperature selector, inside air temperature sensor,
outside air temperature sensor and sunload sensor and
selects any of the following positions by controlling the
position of the air intake control door.
• FRESH position (FRE)
• RECIRCULATION position (REC)
• MIX position (MIX)
Air Conditioning System: Automatic Type 7B-39
A/C Compressor Relay Control
S7RW0A7221002
HVAC control module outputs A/C switch ON signal to
ECM via BCM when the vehicle state satisfy conditions
described below.
• A/C switch is ON
• Evaporator temperature is higher than specified value
• Evaporator temperature sensor malfunction is not
detected
Communication of ECM and BCM is established by CAN
(Controller Area Network). (For more detail of CAN
communication, refer to "CAN Communication System
Description in Section 1A").
ECM turns ON the A/C compressor relay when the
vehicle state satisfy conditions described below.
• A/C switch ON signal is inputted
• A/C refrigerant pressure is within specified range
• Engine speed is within specified range
• Engine coolant temperature is lower than specified
value
• Throttle opening is lower than specified value
• Vehicle is not in either state of starting or quick
acceleration
• ECT sensor malfunction is not detected
• A/C refrigerant pressure sensor malfunction is not
detected
Condenser Cooling Fan Relay Control
ECM turn ON the condenser cooling fan relay at the
same time when ECM turn ON the A/C compressor
relay.
Sub-Cool A/C System Description
Refer to "Sub-Cool A/C System Description: Manual
Type".
S7RW0A7221003
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Troubleshooting
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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.
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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.
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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.
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