SRS - Diagnostic Code Clearing
90lexus05 ELECTRICAL 004 12-28-90 LS400, ES250Title CLEARING SRS DIAGNOSTIC CODES
When the SRS warning light illuminates, this indicates that a diagnostic code has been set the in SRS ECU memory. The following is the procedure for clearing codes stored in the SRS ECU memory.
Figure 1:
OUTPUT DIAGNOSTIC CODE:
^ Turn the ignition switch to the "ACC" or "ON" position.
^ Connect terminals Tc and E1 of the TDCL connector (figure 1) together with SST 09843-18020.
NOTICE: Take care not to connect your SST to the incorrect terminals.
^ The SRS warning light will begin flashing stored diagnostic code(s).
Figure 2:
READING A DIAGNOSTIC CODE:
^ Normal code indication. The light will blink 2 times per second.
^ Malfunction code indication. All diagnostic codes are two digits in length. The light will flash the first digit at 0.5 second intervals between flashes, pause for 1.5 seconds, then flash the second digit at 0.5 second intervals between flashes. A 2.5 second pause will take place before the next code is output (in case of more than one code being set). Finally, a 4 second pause will occur when the system starts repeating stored codes again. (See Figure 2)
DIAGNOSTIC CODE CHECK (Continued):
The following is a summary of diagnostic codes. Refer to the SRS section of the appropriate repair manual for further information.
CLEARING DIAGNOSTIC CODES:
^ Clear diagnostic codes 11 through 31 by disconnecting the ground terminal to the battery then reconnecting it after 10 seconds (Code 41 requires a special procedure).
NOTICE: It is important to remember to have the ignition switch in the LOCK position when connecting the battery after the code clearing procedure. If the battery is connected with the ignition switch in the ACC or ON position, there is a possibility the diagnostic system will not function properly.
^ Code 41 will remain in backup memory after this procedure as a safety function to indicate that a previous diagnostic code existed.
CLEARING CODE 41
^ To clear backup memory of code 41, a special procedure described in the repair manual is required. This procedure sends a message to the SRS computer telling it to reset and clear all codes. However, timing is critical during this procedure and it can be difficult.
PROCEDURE:
^ The following is an alternate procedure for clearing Code 41 that is not as complicated to perform as the procedure described in the repair manual.
1. With the engine off, connect service wires to terminals Tc and AB of the TDCL connector located in drivers side lower dash area (see Figure 3).
NOTE: Make sure you use a good body ground and that the service wires make proper contact with the terminals.
2. Turn the ignition switch to "ACC" or "ON" and wait approximately six (6) seconds (until the SRS warning light goes out).
3. Starting with the Tc terminal, apply body ground alternately to terminal Tc and terminal AB at 0.5 second intervals. Repeat this for three (3) cycles as shown in Figure 4.
4. Finish with the application of ground to terminal Tc (terminal AB should be open at this time).
5. Cancellation is completed when the SRS Warning Light starts to blink very quickly (64 millisecond cycle).
6. Remove the service wires.