ECU GREAT WALL HOVER 2006 Service Owner's Manual

Safety airbag-6
brown whitered
diagnosis plug
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Failure judgment
1. Failure record (failure code storage)
When ECU determines the error through the cyclic diagnosis and test, SRS-ECU should saves the corresponding code, first
judgment time, final judgment time and number of occurrence in EEPROM.
RS-ECU can stores 6 failures at most, under voltage failure and two collision records (front and side).
Failure code approved by SRS-ECU
Serial No. Failure description Debugging
1 Ignition loop 1 (driver ’s front airbag), resistance is too high or open-circuit. Can
2 Ignition loop 1 (driver ’s side front airbag), resistance is too low or short-circuit Can
3 Ignition loop 1 (driver ’s side front airbag), grounding Can
4 Ignition loop 1 (driver’s side front airbag), connected to power supply Can
5 Ignition loop 2 (passenger side front airbag), resistance is too high or open-circuit. Can
6 Ignition loop 2 (passenger side front airbag), resistance is too low or short-circuit Can
7 Ignition loop 2 (passenger side front airbag), connect ed t o power supply Can
8 Ignition loop 2 (passenger side front airbag), connect ed t o power supply Can
9 Power voltage is high Can
10 Power voltage is low Can
11 Alarm light failure, connect ed to power supply or lamp is short-circuit Can
12 Alarm lamp is failure- grounding or filament is open-circuit. Can
13 Shortage/failure of algorithm parameter Cannot (replace the
SRS-ECU)
14 The front collision is recorded Cannot (replace the
SRS-ECU)
15 Communication failure Can
16 Internal failure (refer to following table) Cannot (replace the
SRS-ECU)

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Description of flash code
The failure code transmission is completed by SRS-ECU’s input to the defined diagnostic scanner through the maintenance system’s
serial data interface. (X-431 diagnostic scanner) Failure code of diagnosis
Failure Failure code Flash code
1 No storage error $12
2 Front airbag driver’s, high resistance $9,021 $21
3 Front airbag driver’s , low resistance $9,022 $22
4 Front airbag driver ’s, short-circuit of GND $9,024 $24
5 front airbag driver ’s , short –circuit of VBATT $9,025 $25
6 front airbag passenger, high resistance $9,015 $15
7 front airbag passenger, low resistance $9,016 $16
8 front airbag passenger , short-circuit of GND $9,018 $18
9 Front airbag passenger , short-circuit of VBTT $9,019 $19
10 High voltage of battery $9,031 $31
11 Low voltage of battery $9,032 $32
12 Failure of alarm lamp $9,061 $61
13 Internal failure (replace SDM) $9,071 $71
14 Front collision record $9,051 $51
15 Side collision driver’s record $9,056 $56
16 Side collision passenger record $9,057 $57
17 Retightened safety belt collision $9,058 $58
18 Beyond the allowable repeat usage times $9,054 $54
3. Interior failure
The micro controller can test the following items not only in starting detection but also in cyclic diagnosis detection.
a. Ignition circuit triggers the transistor: The high-side transistor is detected not only in the starting detection but also in the
circulation diagnosis. But for the low-side transistor is opened when is connected to power supply directly, so the low-side
transistor only can be detected in the starting detection to avoid the misexplosion.
b. The ignition voltage is provided by the booster transformer.
c. The acceleration sensor is detected by itself when start the detection.
d. Allowable deviation scope of acceleration sensor in circulation diagnosis.
e. Micro controller includes (AD converter, ROM, RAM etc.)
f. Status of safety sensor
Cautions:
Connector of explosion tube circuit has the short-circuit bar. When the connector is not connected, the end (+) of
explosion tube is connected to end (-) directly to prevent the failure outspread caused by static. When the connector
is bas and short-circuit bar is connected, the failure may not be eliminated.
An external watch dog can detect the operating status of micro controller. It can trigger the watchdog when the micro con
troller has failure. The watch dog will reset the micro-controller and light the alarm lamp.

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Internal failure determined by SRS-ECU
Serial
No. List of failure Description of failure
1 Micro-controller AD converter or EEPROM is faulty (the micro controller will be reset
and alarm lamp is light when the RAM has failure.)
2 Driver’s front airbag ignition loop Enable the failure
Measure the failure of loop
3 Passenger front airbag ignition loop
(if realized) Enable the failure
Measure the failure of loop
4 Seat safety belt preloaded ignition loop
(if realized) Enable the failure
Measure the failure of loop
5 Passenger side safety belt preloaded
ignition loop (if realized) Enable the failure
Measure the failure of loop
6 Driver’s side airbag ignition loop
(if realized) Enable the failure
Measure the failure of loop
7 Passenger side airbag ignition loop
(if realized ) Enable the failure
Measure the failure of loop
8 Maximum times of explosion of safet y
belt pre-tightener Reach the maximum value 6
9 Holding time of ECU ener gy
(self-supply time) Too short
10 Accelerometer Deviation range
Sensor not in constant, stable model
Sensor tests the failure itself
11 The measurement of ignition loop is
rejected continuously No cycling diagnosis test (duplicated calculation)
12 Safety sensor Calculate the safety sensor open-loop using the method that power-off
for 2 or more than 2 seconds is considered as passing
13 Initial firing current All initial firing current in normal status when the front airbag releases.
14 The ignition of side airbag is not
determined. Though SRS-ECU has received ignition information for 5 times during
HSIS cycling ignition, the ignition can not be determined due to the side
safety..

Debug the failure codes
Approach 1. The failure codes will be debugged following the ECU’s receipt from the X-431 diagnostic tester of the debugging
failure codes order through the serial interface, however, if an internal failure code is recorded or one impact is
recorded, the debugging will not be executed.
Approach 2. Ground 488# line for 5 times in 10 seconds to debug the failure codes.
Failure status display (alarm lamp keeps illuminating).
1. Bulb test
SRS-ECU will light the alarm lamp in order to test the bulb after working voltage is provided to it through the battery. The lamp
will flash for 6 times and then extinguish at 1HZ in the initial phase. The alarm lamp will keep illuminating after the working
voltage is provided in order to inform the driver’s system failures. The alarm lamp will keep illuminating for 6 seconds after the
ignition on and then be extinguished if the history-accumulated failures are less than five times. In the initial phase, SRS-ECU will
not prepare to test impact and stop release till the circuit is stable. Therefore, alarm lamp’s display manner will be one of
following projects in the initial phase. (Table 4.9).
Project 1. If the impact is recorded or the number of history accumulated failures is or more than 5,the alarm lamp will keep
illuminating, simultaneously, it will also keep illuminating if there is a possible explosion failure.

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Project 3 functional working (neither possible explosion failure or historical failure).
Table 4.9 indicator lamp’s activities after ignition
2.Failure indication
The alarm lamp will indicate it in case any failure arises. If the external failure is a historical one, the indication will be called off. If
the number of history-accumulated failures is or more than 5, the alarm lamp will keep illuminating albeit no failure emerges. The
case of low power will be excluded.
A displayed or historical failure can but only be reconfigured by the service personnel. An internal failure or impact record can not
be reconfigured, in these cases, SRS-ECU must be replaced.
3.Micro controller-independent alarm lamp illumination
The micro-controller in clear failure status can not work therefore can not control the alarm lamp. In this case, the alarm lamp
will be directly lighted via suitable circuit despite of the micro-controller. As following,
The battery for SRS-ECU fails, the alarm lamp will be continuously lighted through the lamp drive function.
b. No internal working voltage, the alarm lamp keeps illuminating
c. Reconfiguration caused by watchdog’s trigging failure, the alarm lamp flashes.
d. No work of micro-controller, the alarm lamp keeps illuminating
e. Incomplete plugging-in of SRS-ECU connector, the alarm lamp keeps illuminating via shoring bar Next explain the diagnostic
procedure by taking some examples
If the alarm lamp is found keeping illuminating, please test it according to the following procedure even it extinguishes finally.
First test the failure region with the scanner followed by the test in the failure region with the corresponding approaches and
steps.
a If an internal failure or the explosion of safety airbag is scanned, replace the SRS-ECU
b.Troubleshooting Project 2. The number of history- accumulated failures is or more than one and less than 5. (The case of low power is excluded)

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1. Extinguishments of safety airbag system alarm lamp
Troubleshooting
Extinguishments or normal-light of alarm lamp
NO . Troubleshooting item Description
1 T he warning la mp of safety a irbag
system is not displayed. Safety airbag system warns circuit failure
2 T he warning la mp of safety a irbag
system is light normally. Safety airbag system warns circuit failure or external
failure.

1 Extinguishments of safety airbag system alarm lamp
Test status Safety airbag system warns circuit failure.
Possible causes No voltage (fuse shutoff)
Combined instrument failure
Failure of wiring harness between instrument cluster and ECU unit

Diagnostic procedure
When first carry out failure test, joggle the wiring harness and plug to test whether there is periodical bad contact in the circuit, if
it so, please confirm whether the plug, terminal and wiring harness well connected and in good condition. If it is not any of previous
cases, operate according to the following steps.
Procedure Te s t Operation
Ye s Place the ignition switch in LOCK
position followed by next step
1 Test other wiring harness and instrument cluster
indicator lamp
·place the ignition switch in ON position
·light other alarm and indicator lamps No Test the instrument cluster power-supply
system and grounding s ystem (fuse), then
go to step 5.
Yes Next step
2 Bulb test
Warning:
Incorrect handling with the safety airbag system
units will cause the safety airbag’s improper
release and pretension of safety belt, which will
lead to serene accidents. Please read safety airbag
service warning before handling the safety airbag
units.
·Place the ignition switch in LOCK position。
·shut off accumulator negative line and keep the
status for at least 60 seconds.
·Remove the combined instrument.
Test the connection between the two
corresponding stitches of safety airbag alarm lamp No





Rep la ce th e b ulb of a larm la mp.

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2. Normal-light of safety airbag system indicator lamp
2 Normal-light of safety airbag system alarm lamp
Test status Normal-light of safety airbag system alarm lamp
Possible causes Insufficient battery voltage
ECU internal failure
Combined instrument safety airbag alarm lamp failure
ECU plug misconnects
Combined instrument plug bad-contact
ECU power-supply fuse shutoff or bad contact
Misconnection of ECU plug terminal
Bad contact between ECU plug terminal and grounding wiring
harness.
Driver ’s or passengers’ side safety airbag circuit failure.

Procedure Te s t Operation
Yes Next procedure.
3 Test the wiring harness connection between ECU
unit and instrument cluster.
·Place the ignition switch in LOCK position。
·shut off accumulator negative line
·shut off the instrument cluster plug
·test the connection b etween alarm lamp circuit
and its relative circuits No Replace the wiring harness and get into
step 5

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Begin the test with diagnostic communication with special diagnostic device (X-431 diagnostic tester) and ECU
to find out the failure causes, do the next test providing communication is not successful.
Procedure Te s t Operation
Yes Next procedure
1 Test the battery
Test the battery voltage
Is the voltage higher 9V? No Insufficient battery supply.
Test the charging/discharging
system, then go to step 5.
Yes Next step
2 Test the wiring harness connection between ECU and
combined instrument.
Place the ignition switch in LO C K position。
Shut off the battery negative.
O pen the central channel guard plate.
Shut off the instrument combined connector clip
Connect the negative of battery
Place the ignition switch in ON position.
Check whether the instrument connector clip terminal
voltage is 12V(power supply and instrument line) No Check the circuit and continue the
operation according to step 5.
Yes Next step
3 Place the ignition switch in LO C K position。
Check the connection of corresponding terminals between
instrument connector clip and diagnostic interface
(diagnose the two ends of K-line) No Repair or replace the wiring
harness and continue according to
step 5
Yes Next step
3 Make sure the shutoff of accumulator negative line and
keep the status for at least 1 minute.
Shut off ECU connector clip
Shut off the instrument cluster plug.
Connect the ECU plug terminal 5,7,9 and instrument
cluster plug? No Replace the wiring harness and
step 5
Yes Replace ECU
4 Remove EC U to check the condition of term inal and
whether the shorting bar is broken.
No Reconnect EC U connector clip
and next step.
Yes Troubleshooting followed by the
explanations to customers upon
the repair ing pro ced ur e.
5
Make sure that the failure will never reoccur after
repairing.
Place the ignition switch in LO C K position。
Shut off accumulator negative line and keep the status for
at least 1 m in ute.
Connect all ECU plugs
Connect the driver’s side safety airbag combined
instrum ent p lug
Connect the passengers’ side safety airbag combined
instrum ent p lug
Connect the driver and passengers’ side pretension safety
belts plugs.
(Vehicles with pretension safety-b elts)
Connect clock spring plug
Connect the accumulator negative line
Place the ignition switch in ON position
Does the safety airbag alarm lamp work functionally? No Retest the failure symptoms;
repeat from step 1 if the failure
reoccurs.

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Impact-vehicle diagnosis
Test SRS-ECU diagnostic signals
1. Connect the (X-431 diagnostic test’s) diagnostic joint
2. Read the diagnostic results with X-431 diagnostic tester
Repairing procedure
1.When safety airbag is released.
The following parts should be replaced with new ones
a. Passengers’ side safety airbag module
b. SRS-ECU
c. Driver’s side safety airbag module
2 Check the following parts; replace them with new ones providing something wrong with them.
a. Clock spring
b. Steering-wheel, steering column, bottom steering shaft module
3.Driver’s side safety airbag module’s installation status towards the steering wheel.
a. Check whether abnormal knocking is with the steering wheel, its activity is in good condition and its clearance is normal.
b. Check whether the wiring harness joint is broken and its terminal is deformed.
Caution: Due to the impact, the diagnostic instrument cannot communicate with SRS-ECU when accumulator is lack of
power, in this case, check and maintain the instrument panel wiring harness or utilize the extension power supply.

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1. Check whether depression, crack or deformation is with the SRS-ECU bracket.
2. Check whether the joint is broken and terminal is deformed
3. Check SRS-ECU bracket’s installation status
a. Check whether depression, crack or deformation is with the shroud
b. Check whether the joint is broken, terminal is deformed and wiring harness is meshed.
c. Check whether depression, crack or deformation is with the gas generator shield.
d. Make sure the direction of the arrow is straightforward
4. Check the installation status of safety airbag module.
Driver’s side safety airbag module (the following Figure)
generator
bracketconnect the hornconnect the driver’s side
module
Clock spring (right Figure)
1. Check whether the joint and protecting tube are broken and the terminal is deformed.
2. Check whether the shield is deformed.
Steering wheel, steering column and bottom steering shaft module
1. Check the installation status of driver’s side safety airbag module
2. Check whether abnormal knocking is with the steering wheel and its clearance is normal
Passengers’ side safety airbag module (the following Figure)
1. Check the installation status of passengers’ side safety airbag module
2. Check whether the shield is deformed

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Wiring harness joint (instrument cluster wiring harness)
Check whether the wiring harness is well installed, the joint is broken and the terminal is deformed.
Warning
The attentions for use and maintenance for SRS safety airbag are displayed in the Figure. Operate according to the sign and, the
destructed and dirty sign must be replaced with a new one steering
wheel in Figure6-1
Driver’s side safety airbag module in Figure 6.2
Clock spring in Figure 6.3
SRS-ECU in Figure 6.4
Sun visor in Figure 6.5
Passengers’ side safety airbag module in Figure 6.6
Passenger side airbag (PAB)