System Readiness Test (SRT) Code
System Readiness Test (SRT) code is specified in Service $01 of SAE J1979.
As part of an enhanced emissions test for Inspection & Maintenance (I/M), certain states require the status of SRT be used to indicate whether the ECM has completed self-diagnosis of major emission systems and components. Completion must be verified in order for the emissions inspection to proceed.
If a vehicle is rejected for a State emissions inspection due to one or more SRT items indicating "INCMP", use the information in this Service Information to set the SRT to "CMPLT".
In most cases the ECM will automatically complete its self-diagnosis cycle during normal usage, and the SRT status will indicate "CMPLT" for each application system. Once set as "CMPLT", the SRT status remains "CMPLT" until the self-diagnosis memory is erased.
Occasionally, certain portions of the self-diagnostic test may not be completed as a result of the customer's normal driving pattern; the SRT will indicate "INCMP" for these items.
If, during the state emissions inspection, the SRT indicates "CMPLT" for all test items, the inspector will continue with the emissions test. However, if the SRT indicates "INCMP" for one or more of the SRT items the vehicle is returned to the customer untested.
SRT Item
The table below shows required self-diagnostic items to set the SRT to "CMPLT".
| SRT item (CONSULT-III indication) | Performance Priority(1) | Required self-diagnostic items to set the SRT to "CMPLT" | Corresponding DTC No. | ||
|---|---|---|---|---|---|
| CATALYST | 2 | Three way catalyst function | P0420, P0430 | ||
| EVAP SYSTEM | 2 | EVAP control system purge flow monitoring | P0441 | ||
| 1 | EVAP control system | P0442 | |||
| 2 | EVAP control system | P0456 | |||
| HO2S | 2 | Air fuel ratio (A/F) sensor 1 | P0133, P0153 | ||
| Heated oxygen sensor 2 | P0137, P0157 | ||||
| Heated oxygen sensor 2 | P0138, P0158 | ||||
| Heated oxygen sensor 2 | P0139, P0159 | ||||
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SRT Set Timing
SRT is set as "CMPLT" after self-diagnosis has been performed one or more times. Completion of SRT is done regardless of whether the result is OK or NG. The set timing is different between OK and NG results and is shown in the table below.
| Self-diagnosis result | Example | |||||
|---|---|---|---|---|---|---|
| Diagnosis | Ignition cycle → ON → OFF → ON → OFF → ON → OFF → ON → |
|||||
| All OK | Case 1 | P0400 | OK (1) | - (1) | OK (2) | - (2) |
| P0402 | OK (1) | - (1) | - (1) | OK (2) | ||
| P1402 | OK (1) | OK (2) | - (2) | - (2) | ||
| SRT of EGR | "CMPLT" | "CMPLT" | "CMPLT" | "CMPLT" | ||
| Case 2 | P0400 | OK (1) | - (1) | - (1) | - (1) | |
| P0402 | - (0) | - (0) | OK (1) | - (1) | ||
| P1402 | OK (1) | OK (2) | - (2) | - (2) | ||
| SRT of EGR | "INCMP" | "INCMP" | "CMPLT" | "CMPLT" | ||
| NG exists | Case 3 | P0400 | OK | OK | - | - |
| P0402 | - | - | - | - | ||
| P1402 | NG | - | NG | NG (Consecutive NG) | ||
| (1st trip) DTC | 1st trip DTC | - | 1st trip DTC | DTC (= MIL ON) | ||
| SRT of EGR | "INCMP" | "INCMP" | "INCMP" | "CMPLT" | ||
| OK: Self-diagnosis is carried out and the result is OK. NG: Self-diagnosis is carried out and the result is NG. -: Self-diagnosis is not carried out. |
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When all SRT related self-diagnoses showed OK results in a single cycle (Ignition OFF-ON-OFF), the SRT will indicate "CMPLT". → Case 1 above
When all SRT related self-diagnoses showed OK results through several different cycles, the SRT will indicate "CMPLT" at the time the respective self-diagnoses have at least one OK result. → Case 2 above
If one or more SRT related self-diagnoses showed NG results in 2 consecutive cycles, the SRT will also indicate "CMPLT". → Case 3 above
The table above shows that the minimum number of cycles for setting SRT as "INCMP" is one (1) for each self-diagnosis (Case 1 & 2) or two (2) for one of self-diagnoses (Case 3). However, in preparation for the state emissions inspection, it is unnecessary for each self-diagnosis to be executed twice (Case 3) for the following reasons:
- The SRT will indicate "CMPLT" at the time the respective self-diagnoses have one (1) OK result.
- The emissions inspection requires "CMPLT" of the SRT only with OK self-diagnosis results.
- When, during SRT driving pattern, 1st trip DTC (NG) is detected prior to "CMPLT" of SRT, the self-diagnosis memory must be erased from ECM after repair.
- If the 1st trip DTC is erased, all the SRT will indicate "INCMP".NOTE: SRT can be set as "CMPLT" together with the DTC(s). Therefore, DTC check must always be carried out prior to the state emission inspection even though the SRT indicates "CMPLT".
SRT Service Procedure
If a vehicle has failed the state emissions inspection due to one or more SRT items indicating "INCMP", review the flowchart diagnostic sequence in the figure.
How to Display SRT Status
WITH CONSULT-III
Selecting "SRT STATUS" in "DTC CONFIRMATION" mode with CONSULT-III.
For items whose SRT codes are set, a "CMPLT" is displayed on the CONSULT-III screen; for items whose SRT codes are not set, "INCMP" is displayed.
WITH GST
Selecting Service $01 with GST (Generic Scan Tool)
NO TOOLS
A SRT code itself can not be displayed while only SRT status can be.
- Turn ignition switch ON and wait 20 seconds.
- SRT status is indicated as shown in the figure below.
- When all SRT codes are set, MIL lights up continuously.
- When any SRT codes are not set, MIL will flash periodically for 10 seconds.
How to Set SRT Code
To set all SRT codes, self-diagnosis for the items indicated above must be performed one or more times. Each diagnosis may require a long period of actual driving under various conditions.
WITH CONSULT-III
Perform corresponding DTC Confirmation Procedure one by one based on Performance Priority in the table on "SRT Item".
WITHOUT CONSULT-III
The most efficient driving pattern in which SRT codes can be properly set is explained in the following information. The driving pattern should be performed one or more times to set all SRT codes.
Driving Pattern
- The time required for each diagnosis varies with road surface conditions, weather, altitude, individual driving habits, etc.
Zone A refers to the range where the time, required for the diagnosis under normal conditions*, is the shortest.
Zone B refers to the range where the diagnosis can still be performed if the diagnosis is not completed within zone A.
*: Normal conditions refer to the following:
- Sea level
- Flat road
- Ambient air temperature: 20 - 30°C (68 - 86°F)
- Diagnosis is performed as quickly as possible under normal conditions.
Under different conditions [For example: ambient air temperature other than 20 - 30°C (68 - 86°F)], diagnosis may also be performed.
Pattern 1:
- The engine is started at the engine coolant temperature of -10 to 35°C (14 to 95°F) (where the voltage between the ECM terminal 73 and ground is 3.0 - 4.3V).
- The engine must be operated at idle speed until the engine coolant temperature is greater than 70°C (158°F) (where the voltage between the ECM terminal 73 and ground is lower than 1.4V).
- The engine is started at the fuel tank temperature of warmer than 0°C (32°F) (where the voltage between the ECM terminal 107 and ground is less than 4.1V).
Pattern 2:
- When steady-state driving is performed again even after it is interrupted, each diagnosis can be conducted. In this case, the time required for diagnosis may be extended.
Pattern 3:
- Operate vehicle following the driving pattern shown in the figure.
- Release the accelerator pedal during decelerating vehicle speed from 90 km/h (56 MPH) to 0 km/h (0 MPH).
Pattern 4:
- The accelerator pedal must be held very steady during steady-state driving.
- If the accelerator pedal is moved, the test must be conducted all over again.
*1: Depress the accelerator pedal until vehicle speed is 90 km/h (56 MPH), then release the accelerator pedal and keep it released for more than 10 seconds. Depress the accelerator pedal until vehicle speed is 90 km/h (56 MPH) again.
*2: Checking the vehicle speed with GST is advised.
Suggested Transmission Gear Position
Set the selector lever in the D position with the overdrive switch turned ON.