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250(2) Trouble indication
1In case of a trouble, the warning light will indicate. If the external trouble is a history trouble, the indication
will be cancelled. When the history trouble happens for no less than 5 times, the indicator light will remain
on even if there is no more trouble. "Low battery voltage" shall not be counted in the total number of
troubles.
2Only a service worker can reset a displayed or history trouble. The internal troubles of a SRS ECU
(HAE2.5) or the "crash record" of a trouble cannot be reset, in which case the SRS ECU (HAE2.5) shall
be replaced.
(3) Microcontroller-independent warning light on
Microcontroller with definitive troubles cannot fulfill its functions, thus cannot control the warning light. In
this case, the warning light will light up through proper circuit regardless of the microcontroller as stated
below:
yMalfunction of the battery supplying power to SRS ECU (HAE2.5): the warning lights are turned
on continuously by means of the drive function of the selfcheck light.
yLoss of internal working voltage: the warning light remains on.
yReset due to trigger failure of the watchdog: the warning light blinks.
yMicrocontroller out of work: the warning light always lights up.
yIncomplete insertion of SRS ECU (HAE2.5) connector: the warning light remains on by means of
a shorting bar.
The diagnostic procedures can well be illustrated as follows:
If it is found that the SRS warning light remains on, follow the undermentioned procedures to check even if
the light goes out eventually. First, a scan meter is used to check the location of the trouble.
Then£¬go on with the checking in accordance with specific methods and procedures for the correspondent
location.
a. If the result indicates that it is an internal trouble or that the SRS is already detonated, replace the
ECU directly.
b. Troubleshooting.
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251Section 2 TroubleshootingI. LIST OF TROUBLES1. SRS warning light OFFDIAGNOSTIC PROCEDURESWhen performing the first diagnostic check, it is advised to shake slightly the harness and connector to see if
there is any discontinuous poor contact in circuit. If there is such a problem, make sure that the connections
of the connector, terminals and wire harness are correct and undamaged. Otherwise, follow these procedures:
(1) Check other wire harnesses and instrument cluster indicator lights
1Turn the ignition switch ON.
2Any other light on?
Yes: turn the ignition switch to LOCK, and continue with the next step.
No: check the power supply and ground system (fuse) of the instrument cluster, and continue with step 5.
(2) Check light bulb
CAUTION:
Mishandling of SRS components may release unexpectedly airbag and seat belt pretensioner, probably lead-
ing to a serious accident. Read the service cautions before handling a SRS component.
1Turn the ignition switch to LOCK.
2Disconnect the negative (-) terminal cable from the battery and wait for at least 60s.
3Remove the instrument cluster.
4Measure and see if the two pins of the SRS warning light is triggered.
Yes: continue with next step.
No: replace the bulb of the warning light.
Trouble Che c king Status P ossible Ca use
·Loss of voltage (fuse c irc uit bre a k)
·Instrument cluster trouble
·Trouble of wire harness between instrument
cluster and ECU SRS warning light OFF SRS wa rning c ircuit trouble1 SRS warning light is OFF SRS wa rning c irc uit trouble. No. Trouble shooting Ite ms De sc ription
2 SRS warning light re mains on SRS wa rning circ uit trouble or exte rna l trouble.
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252(3)Check the connection between ECU and instrument cluster
1Turn the ignition switch to LOCK.
2Disconnect the negative (-) terminal cable from the battery.
3Disconnect the connector of instrument cluster.
4Check if the related circuits of the warning light are connected or not.
Yes: continue with next step.
No: replace the wire harness, and then continue with step 5.
2. SRS warning light remains on.DIAGNOSTIC PROCEDURESTo begin the check, first use special diagnostic instruments and ECU to perform communication diagnosis
and find out the causes of the trouble. If the communication fails, continue with the following procedures:
(1) Check battery
1Check battery voltage.
2Is voltage higher than 9V?
Yes: continue with next step.
No: Insufficient battery supply. Check the charging/discharging system, and then continue with step (5).
(2) Check the continuity of the wire harness between ECU and instrument cluster
1Turn the ignition switch to LOCK.
2Disconnect negative (-) terminal cable from the battery.
3Open the guard plate of the central passage.
4Disconnect the connector of the instrument cluster.
5Connect the negative (-) terminal cable of the battery.
6Turn the ignition switch ON.
7Check whether the voltage of the connector terminal of the instrument is 12V (power supply and instrument
connecting wire).Trouble Che cking Sta tus P ossible Cause z Insufficient battery supply z ECU internal trouble z SRS wa rning light trouble of instrument c luste r z Improper connection of ECU connector z P oor c ontac t of instrume nt c luste r c onne c tor z Ope n circ uit or poor c onta c t of ECU power supply fuse z P oor c onne c tion of ECU connec tor te rmina l z P oor conta ct of the wire ha rne ss be twe en ECU
connec tor te rmina l a nd ground z Drive r or pa ssenge r side circ uit trouble of SRS SRS wa rning light
remains onSRS warning light
remains on
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253Yes: continue with next step.
No: check the circuit, repair it and continue with step (5).
8Turn the ignition switch to LOCK.
9Check the continuity of the terminal of instrument connector and that of diagnostic interface (check the
two ends of K line).
Yes: continue with next step.
No: repair or replace the wire harness. Continue with step (5).
VMake sure to disconnect the negative terminal cable from the battery and wait for at least 60s.Disconnect
the ECU connector. 11Disconnect the connectors of the instrument cluster 12 Are the connector terminals 5, 7 and 9 and those of instrument cluster continuity?
Yes: continue with next step.
No: replace the wire harness, and then continue with step (5). 13Remove ECU and see whether the terminals are in good condition and whether the shorting bar is
broken.
Yes: replace the ECU.
No: reconnect the ECU connector, and then continue with next step.
(3) Make sure of the nonrecurrence of the trouble after repair
1Turn the ignition switch to LOCK.
2Disconnect the negative (-) terminal cable from the battery and wait for at least 60s.
3Connect all the ECU connectors.
4Connect the connector of driver airbag assembly.
5Connect the connector of passenger airbag assembly.
6Connect the connectors of driver and passenger seat belt pretensioners (vehicle with pretensioner).
7Connect clock spring connector.
8Connect the negative (-) terminal cable of the battery.
9Turn the ignition switch to ON.
VIs the SRS warning light working normal?
Yes: the trouble is eliminated. Explain the repair procedures to the Customer.
No: recheck symptoms of the trouble. Repeat these procedures from the first step if the trouble reoccurs.
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