Air Suspension System - Diagnostics: Pre-Check

DIAGNOSIS SYSTEM

Inspect the battery voltage.
Battery voltage: 11 to 14 V

If the voltage is below 11 V, recharge the battery before proceeding.

Check DLC3.

The vehicle's suspension control ECU uses ISO 9141-2 for communication. The terminal arrangement of DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.

Verify the conditions listed in the table below:

Fig 1: Identifying DLC3 Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DLC3 TERMINALS CONNECTION/VOLTAGE OR RESISTANCE

Terminal No.	Disc.	Connection/Voltage or Resistance	Condition
7	SIL	Bus + Line/Pulse generation	During transmission
4	CG	Chassis Ground to Body Ground/1 Ω or less	Always
16	BAT	Battery Positive to Body Ground/10 to 14 V	Always

HINT:

If the hand-held tester display shows UNABLE TO CONNECT TO VEHICLE when the cable of the hand-held tester is connected to DLC3, the ignition switch is turned to the ON position and the tester is operated, there is a problem on the vehicle side or tester side.

If communication is normal when the tester is connected to another vehicle, inspect DLC3 on the original vehicle.
If communication is still not possible when the tool is connected to another vehicle, the problem is probably in the tester itself, so consult the Service Department listed in the tester's instruction manual.

Indicator lamp
1. During the vehicle height control operation, the height control OFF indicator lamp blinks when there is any malfunction in the Air Suspension System.
  NOTE:
  - When the malfunction has been corrected, the height control OFF indicator lamp does not come on.
  - The height control OFF indicator lamp does not illuminate when all problems occur (See DIAGNOSTIC TROUBLE CODE CHART for the items that make the height control OFF indicator lamp comes on).
    
    Fig 2: Identifying Height Control OFF Indicator Lamp On Combination Meter
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
DTCs (Normal mode)
1. DTCs are memorized in the suspension control ECU and read by the blinks of the height control OFF indicator lamp or using the hand-held tester (See PRE-CHECK for the procedure of DTCs check).
Test mode
1. By switching from normal mode into test mode (input signal check), you can inspect the stop lamp switch assy, rear speed sensor, height control switch, height control OFF switch, engine speed signal, access mode switch (See step f).

CHECK INDICATOR LAMP

Turn the ignition switch to the ON position.

Check that the height control OFF indicator lamp, height control indicator lamp and the access mode indicator lamp come on for 2 sec.

If the indicator check result is not normal, proceed to the troubleshooting for the indicator lamp circuit.

INDICATOR LAMP CIRCUIT TROUBLESHOOTING

Trouble Area	Refer To
Height control indicator lamp circuit	See HEIGHT CONTROL INDICATOR LAMP CIRCUIT
Height control OFF indicator lamp circuit	See HEIGHT CONTROL OFF INDICATOR LAMP CIRCUIT
Access mode indicator lamp circuit	See ACCESS MODE INDICATOR LAMP CIRCUIT

Fig 3: Identifying Height Control Indicator Lamp Positions

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DTC CHECK (USING SST CHECK WIRE)

Check DTCs.

Using the SST(s), connect terminals TC and CG of DLC3.
SST 09843-18040
Turn the ignition switch to the ON position.

Fig 4: Identifying DLC3 Terminals TC And CG
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Read and record any DTCs from the height control OFF indicator lamp on the combination meter. Refer to Fig 5 for examples of a normal code and codes 13 and 33.

HINT:

If the height control OFF indicator lamp does not blink any DTC codes or the normal code, inspect the height control OFF indicator lamp circuit or TC terminal circuit.

HEIGHT CONTROL OFF INDICATOR LAMP CIRCUIT TROUBLESHOOTING

Trouble Area	Refer To
Height control OFF indicator lamp circuit	HEIGHT CONTROL OFF INDICATOR LAMP CIRCUIT
TC terminal circuit	TC TERMINAL CIRCUIT

Fig 5: Identifying Height Control OFF Indicator Lamp

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If 2 or more malfunctions are indicated at the same time, the lowest numbered DTC is displayed first.

Refer to DIAGNOSTIC TROUBLE CODE CHART for DTC information.
After completing the check, remove the SST(s) from DLC3.
SST 09843-18040

Fig 6: Blinking Pattern Of Height Control OFF Indicator Lamp
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Clear the DTCs.
1. Make sure the ignition switch is OFF.
2. Using the SST(s), connect terminals TC and CG of DLC3.
  SST 09843-18040
  
  Fig 7: Identifying DLC3 Terminals TC And CG
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Turn the ignition switch to the ON position.
4. Clear the DTCs stored in the ECU by depressing the brake pedal 8 times or more within 5 sec.
5. Check that the height control OFF indicator lamp blinks a normal code.
  HINT:
  
  If the fault has not been repaired, the DTC code may still be displayed.
6. Turn the ignition switch to the OFF position.
7. Remove SST(s) from DLC3.
  SST 09843-18040
  
  HINT:
  
  Disconnecting the battery cable during the operation will not erase DTCs in the ECU.
DTC CHECK (USING HAND-HELD TESTER)
1. Check DTCs.
  1. Connect the hand-held tester to DLC3.
  2. Turn the ignition switch to the ON position.
  3. Read the DTCs by following the prompts on the tester screen.
    HINT:
    
    Refer to the hand-held tester operator's manual for further details.
2. Clear the DTCs using the hand-held tester.
  HINT:
  
  After repairing the malfunctions, clear the DTC.
  1. Connect the hand-held tester to DLC3.
  2. Turn the ignition switch to the ON position.
  3. Erase the DTCs following the prompts on the tester screen.
    HINT:
    
    Refer to the hand-held tester operator's manual for further details.

DATA LIST

Connect the hand-held tester to DLC3.
Turn the ignition switch to the ON position.

Following the display on the hand-held tester, read the "DATA LIST".

DATA LIST

Item	Measurement Item/Range (Display)	Normal Condition	Diagnostic Note
VEHICLE SPD	Vehicle speed reading/min.: 0 km/h (0 mph), max.: 255 km/h (158 mph)	Actual vehicle speed	Speed indicated on the combination meter
IG VOLTAGE	ECU power supply voltage/min.: 0 V, max.: 25.5 V	Actual ECU power supply voltage: 10 to 14 V	-
POWER VOLTAGE	+B power source voltage/min.: 0 V, max.: 25.5 V	Actual ECU power supply voltage: 10 to 14 V	-
ENGINE SPD	Cam position sensor reading/min.: 0 rpm, max.: 25,500 rpm	Actual engine speed	Speed indicated on the combination meter
HEIGHT SW DOWN	Height control switch (DOWN)/ON or OFF	ON: Height control switch while pressing "DOWN" button OFF: -	-
HEIGHT SW UP	Height control switch (UP)/ON or OFF	ON: Height control switch while pressing "UP" button OFF: -	-
HEIGHT SW HOLD	Height control OFF switch/ON or OFF	ON: Height control OFF switch pressing OFF: -	-
STOP LIGHT SW	Stop light switch/ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	-
ACCESS MODE SW	Access mode switch/ON or OFF	ON: Access mode switch pressing OFF: -	-
FR HEIGHT	Right front height control sensor reading/min.: -3276.7 mm (-129.004 in.), max.: 3276.8 (129.007 in.)	Min.: -80 mm (-3.15 in.) Max.: 80 mm (3.15 in.)	-
FL HEIGHT	Left front height control sensor reading/min.: -3276.7 mm (-129.004 in.), max.: 3276.8 (129.007 in.)	Min.: -80 mm (-3.15 in.) Max.: 80 mm (3.15 in.)	-
RR HEIGHT	Right rear height control sensor reading/min.: -3276.7 mm (-129.004 in.), max.: 3276.8 mm (129.007 in.)	Min.: -80 mm (-3.15 in.) Max.: 80 mm (3.15 in.)	-
RL HEIGHT	Left rear height control sensor reading/min.: -32776.7 mm (-129.004 in.), max.: 3276.8 mm (129.007 in.)	Min.: -80 mm (-3.15 in.) Max.: 80 mm (3.15 in.)	-
FR ADJUST	Right front height control adjust reading/min.: -3276.7 mm (-129.004 in.), max.: 3276.8 (129.007 in.)	Actual height control adjust value	-
FL ADJUST	Left front height control adjust reading/min.: -3276.7 mm (-129.004 in.), max.: 3276.8 (129.007 in.)	Actual height control adjust value	-
RR ADJUST	Right rear height control adjust reading/min.: -3276.7 mm (-129.004 in.), max.: 3276.8 (129.007 in.)	Actual height control adjust value	-
RL ADJUST	Left rear height control sensor reading/min.: -3276.7 mm (-129.004 in.), max.: 3276.8 (129.007 in.)	Actual height control adjust value	-
FR AFTER ADJUST	Right front height control after adjust reading/min.: -3276.7 mm (-129.004 in.), max.: 3276.8 (129.007 in.)	Min.: -10 mm (-0.39 in.) Max.: 10 mm (0.39 in.)	-
FL AFTER ADJUST	Left front height control after adjust reading/min.: -3276.7 mm (-129.004 in.), max.: 3276.8 (129.007 in.)	Min.: -10 mm (-0.39 in.) Max.: 10 mm (0.39 in.)	-
RR AFTER ADJUST	Right rear height control after adjust reading/min.: -3276.7 mm (-129.004 in.), max.: 3276.8 (129.007 in.)	Min.: -10 mm (-0.39 in.) Max.: 10 mm (0.39 in.)	-
RL AFTER ADJUST	Left rear height control after adjust reading/min.: -3276.7 mm (-129.004 in.), max.: 3276.8 (129.007 in.)	Min.: -10 mm (-0.39 in.) Max.: 10 mm (0.39 in.)	-
RL SOL	Left rear solenoid valve/ON or OFF	ON or OFF	-
RR SOL	Right rear solenoid valve/ON or OFF	ON or OFF	-
FL SOL	Left front solenoid valve/ON or OFF	ON or OFF	-
FR SOL	Right front solenoid valve/ON or OFF	ON or OFF	-
EXHAUST SOL	Exhaust solenoid valve/ON or OFF	ON or OFF	-
MOD2	Mode 2/ON or OFF	2WD:ON or OFF 4WD: ON
MOTOR RELAY	AIR SUS relay/ON or OFF	ON: Compressor operated OFF: Compressor not operated	-
MAIN RELAY	Main relay expectation/ON or OFF	ON	-
RR WHEEL SPD	Right rear wheel speed reading/min.: 0 km/h (0 mph), max.: 255 km/h (158 mph)	Actual right rear wheel speed	Speed indicated on the combination meter
RL WHEEL SPD	Left rear wheel speed reading/min.: 0 km/h (0 mph), max.: 255 km/h (158 mph)	Actual left rear wheel speed	Speed indicated on the combination meter
LOW PRS TNK SOL	Tank solenoid valve/ON or OFF	ON or OFF	-
#CODES	Number of DTC recorded/min.: 0, max.: 255	Min.: 0, Max.: -	-

ACTIVE TEST LIST

Connect the hand-held tester to DLC3.
Turn the ignition switch to the ON position.

Following the display on hand-held tester, perform the "ACTIVE TEST".

ACTIVE TEST LIST

Item	Vehicle Condition/Test Details	Diagnostic Note
FR UP & DOWN	Right front/UP or DOWN	-
FL UP & DOWN	Left front/UP or DOWN	-
RR UP & DOWN	Right rear/UP or DOWN	-
RL UP & DOWN	Left rear/UP or DOWN	-
FR SOL	Turn OFF right front solenoid valve one second after turning it ON	Operation of solenoid (clicking sound) can be heard
FL SOL	Turn OFF left front solenoid valve one second after turning it ON	Operation of solenoid (clicking sound) can be heard
RR SOL	Turn OFF right rear solenoid valve one second after turning it ON	Operation of solenoid (clicking sound) can be heard
RL SOL	Turn OFF left rear solenoid valve one second after turning it ON	Operation of solenoid (clicking sound) can be heard
MOTOR RELAY	AIR SUS relay/ON or OFF	Operation of solenoid (clicking sound) can be heard
LOW PRS TNK SOL	Turn tank solenoid valve/ON or OFF	Operation of solenoid (clicking sound) can be heard

TEST MODE CHECK (USING SST CHECK WIRE)

HINT:

When entering the test mode, the suspension control ECU sets all the test DTCs first.
After completing the input signal operation for each inspection item, the DTCs that are judged normal by the suspension control ECU will be erased.

The DTCs for other inspection items may not be erased when only a certain signal is inspected.
When the test mode returns back to the normal mode, all the test DTCs will be erased.

Procedure for Test Mode.

Make sure that the ignition switch is off.
Set each of the check items in the table below to the condition in Operation (A).
Using the SST(s), connect the terminals TS and CG of DLC3.
SST 09843-18040
Turn the ignition switch to the ON position.

Fig 10: Identifying DLC3 Terminals TS And CG
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check that the height control OFF indicator lamp comes on and goes off at 0.125 second intervals. (4 Hz)

HINT:

If the height control OFF indicator lamp does not blink, inspect the height control OFF indicator lamp circuit or the TS terminal circuit.

HEIGHT CONTROL OFF INDICATOR LAMP CIRCUIT TROUBLESHOOTING

Trouble Area	Refer To
Height control OFF indicator lamp circuit	See HEIGHT CONTROL OFF INDICATOR LAMP CIRCUIT
TS terminal circuit	See TS TERMINAL CIRCUIT

Fig 11: Identifying Height Control OFF Indicator Lamp

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Set each of the check items to the condition in Operation (B).

HINT:

When checking each item, the height control OFF indicator lamp should come on for 1 sec. then continue blinking.
There is no input signal order.

Fig 12: Blinking Pattern Of Height Control OFF Indicator Lamp

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Test mode table:

TEST MODE

Check Item	Operation (A)	Operation (B)
Stop lamp switch signal	OFF (Brake pedal not depressed)	ON (Brake pedal depressed)
Right rear speed sensor signal	Vehicle speed below 20 km/h (12 mph)	Vehicle speed 20 km/h (12 mph) or higher
Left rear speed sensor signal	Vehicle speed below 20 km/h (12 mph)	Vehicle speed 20 km/h (12 mph) or higher
Height control switch signal	Neutral position	Press the height control switch "UP" first and then press "DOWN"
Height control OFF switch signal	OFF (Height control OFF indicator lamp is OFF.)	ON to OFF (Height control OFF switch pushed in 2 times.)
Crankshaft position sensor signal	Engine speed below 2,000 rpm	Engine speed 2,000 rpm or higher
Access mode switch signal	OFF (Access mode switch not pushed in)	ON to OFF (Access mode switch pushed in and released)

Using the SST(s), connect the 3rd terminal of the SST to terminal TC in the DLC3.
SST 09843-18040

Fig 13: Identifying DLC3 Terminals TC, TS & CG
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Read the number of blinks of the height control OFF indicator lamp.

Fig 14: Identifying Height Control OFF Indicator Lamp
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:
- As an example, the blinking patterns of a normal code and code 82 are shown in Fig 15.
- If 2 or more malfunctions are indicated at the same time, the lowest numbered code is displayed first.
- When a DTC or normal code is not output, check the TC terminal circuit on TC TERMINAL CIRCUIT .
Check the malfunction using the code table below.

Fig 15: Blinking Patterns Of Normal Code And Code 82

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Clear the test DTCs and return to normal mode.
HINT:

After repairing the malfunctions, clear the test DTC.
1. Turn the ignition switch off.
2. Disconnect the SST(s) from the terminals of DLC3.
  SST 09843-18040
3. Turn the ignition switch to the ON position.

TEST MODE CHECK (HAND-HELD TESTER)
HINT:
- When entering the test mode, the suspension control ECU sets all the test DTCs first.
  After completing the input signal operation for each inspection item, the DTCs that are determined normal by the suspension control ECU will be erased.
  
  The DTCs for other inspection items may not be erased when only a certain signal is inspected.
- When the test mode returns back to the normal mode, all the test DTCs will be erased.
1. Procedure for Test Mode.
  1. Make sure that the ignition switch is OFF.
  2. Set each of the check items to the condition in Operation (A) in the test mode table.
  3. Connect the hand-held tester to DLC3.
  4. Turn the ignition switch to the ON position.
  5. Select the SIGNAL CHECK mode on the hand-held tester.
  6. Set each of the check items to the condition in Operation (B) in the test mode table.
    HINT:
    
    In step (6), all signals can be checked together.
  7. Read the DTCs by following the prompts on the tester screen.
    HINT:
    
    Refer to the hand-held tester operator's manual for further details.
  8. After completing the input signal check, disconnect the tester and turn the ignition switch off.
  DTC of Air Suspension System test mode function:
  
  If a malfunction code is displayed during the test mode DTC check, check the circuit listed for that code.
  
  Fig 17: Air Suspension System Test Mode Function DTC Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

ADJUST VEHICLE HEIGHT (WHEN USING HAND HELD TESTER)

HINT:

Leave the driver's seat window open to make height control operation easier.

Start the engine.
Change the height control switch to the "N" position.
Check that the blinking for the "N" lamp in the combination meter is on.
Push the access mode switch to the off position.
Stop the engine and turn the ignition switch OFF.

Fig 18: Identifying Height Control Indicator Lamp Positions
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check the vehicle height (calculated value).

HINT:

Refer to Fig 19.

VEHICLE HEIGHT

Front	Measured height B minus A
Rear	Measured height D minus C

Ground clearance of lower front suspension arm No.2 bush set bolt center.
Ground clearance of front wheel center.
Ground clearance of strut rod set bolt center.
Ground clearance of rear wheel center.

Fig 19: Checking Vehicle Height

If the value of the vehicle height is not within the range of the standard value, note the value measured and proceed to the following step.

Standard value table:

VEHICLE HEIGHT STANDARD VALUE

2WD	117 +/- 10 mm (4.602 +/- 0.393 in.)	41 +/- 10 mm (1.618 +/- 0.393 in.)
4WD	112 +/- 10 mm (4.406 +/- 0.393 in.)	36 +/- 10 mm (1.421 +/- 0.393 in.)

The difference between the right and the left sides should be less than 10 mm (0.39 in.).

NOTE: In the case where the difference between the value of the vehicle height and standard value exceeds 80 mm (3.15 in.), this check cannot be performed by using the hand held tester.
In order to perform the check with the hand-held tester, adjust the difference below 80 mm (3.15 in.) without using the hand-held tester. Check the height control sensor sub-assy (See DTC C1711/11 RIGHT FRONT HEIGHT CONTROL SENSOR CIRCUIT, DTC C1712/12 LEFT FRONT HEIGHT CONTROL SENSOR CIRCUIT, DTC C1713/13 RIGHT REAR HEIGHT CONTROL SENSOR CIRCUIT, DTC C1714/14 LEFT REAR HEIGHT CONTROL SENSOR CIRCUIT ).

Connect the hand-held tester to DLC3.

Fig 20: Connecting Hand-Held Tester To DLC3

Turn the ignition switch to the ON position.
Perform the height offset procedure from the AIR SUS menu.

Fig 21: AIR SUS Menu - Height Offset Procedure
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Start the engine.
Change the height control switch to the "HI" position and check that the blinking for the "HI" lamp on the meter has been changed to the illuminating,
Change the height control switch to the "N" position again and get out of the vehicle immediately while the "N" lamp is blinking.
NOTE: Be sure to get out of the vehicle while the lamp is blinking as the height will be changed and the value will not be measured properly if you fail to do so.
Turn the ignition switch to the OFF position from outside of the vehicle after the "N" lamp comes on.
NOTE: Do not touch the vehicle as its height may be changed.

Fig 22: Identifying Height Control Switch Positions

Check the vehicle height again to confirm the value of the vehicle height is within the range of the standard values.

ADJUST VEHICLE HEIGHT (WHEN NOT USING HAND-HELD TESTER)

Start the engine.
Change the height control switch to the "N" position.
Check that the blinking for the "N" lamp on the meter has been changed to the illuminating.
Stop the engine and turn the ignition switch OFF.

Fig 23: Identifying Height Control Switch Positions

Check the vehicle height (calculated value).
HINT:

Leave the driver's seat window open to make height control operation easier.
1. Ground clearance of lower suspension arm No.2 bush set bolt center.
2. Ground clearance of front wheel center.
3. Ground clearance of strut rod set bolt center.
4. Ground clearance of rear wheel center.

If the value of the vehicle height is not within the range of the standard value, note the value measured and proceed to the following step.

Standard value table:

VEHICLE HEIGHT STANDARD VALUES

2WD	117 +/- 10 mm (4.602 +/- 0.393 in.)	41 +/- 10 mm (1.618 +/- 0.393 in.)
4WD	112 +/- 10 mm (4.406 +/- 0.393 in.)	36 +/- 10 mm (1.421 +/- 0.393 in.)

Fig 24: Checking Vehicle Height

Difference between the right and the left sides should be less than 10 mm (0.39 in.).

Adjust the front vehicle height control sensor links.

Fig 25: Adjusting Front Vehicle Height Control Sensor Links
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NOTE:
- Adjust the link of which the value for the vehicle height control is most beyond the range of the standard value first.
- If the values of the front vehicle height and the rear vehicle height are the same, adjust the front vehicle height control sensor link first.
1. Loosen the nut and adjust the link position by moving it up and down along the bracket's hole on the vehicle.
  HINT:
  
  The vehicle height will be changed by approx. 5 mm (0.19 in.) when changing the link by approx. 1 mm (0.04 in.).
2. Tighten the nut on the vehicle height control sensor link.
  Torque: 5.4 N.m (55 kgf.cm, 48 in..lbf)
Adjust the rear vehicle height control sensor links.
1. Loosen the 2 lock-nuts on the vehicle height control sensor link and turn the link to adjust its length.
  HINT:
  - Lengthen the link to raise the vehicle height.
  - Shorten the link to lower the vehicle height.
  - 2WD:
    The vehicle height will be changed by approx. 8 mm (0.31 in.) when turning the rear vehicle height control sensor link around once.
  - 4WD:
    The vehicle height will be changed by approx. 3 mm (0.12 in.) when turning the rear vehicle height control sensor link around once.
  Fig 26: Adjusting Rear Vehicle Height Control Sensor Links
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check if the vehicle height control sensor link dimension (A) shown in the illustration is shorter than the standard value.
  Standard length: 18.0 mm (0.708 in.) or less
  
  Fig 27: Identifying Vehicle Height Control Sensor Link Dimension
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Tighten the 2 lock-nuts on the vehicle height control sensor link.
  Torque: 5.4 N.m (55 kgf.cm, 48 in..lbf)
Check the vehicle height again to confirm the value of the vehicle height is within the range of the standard value,
Adjust the headlight aim only (See ADJUSTMENT ).