- Caterpillar Products:
- All
Caterpillar products listed above with Electronic Controls Modules (ECMs) have a feature to automatically clear Diagnostic Trouble Codes (DTCs) (diagnostics and events) from the log system if the DTCs are not active within a predetermined period of service meter hours (SMH). The auto clear functionality helps to make sure that the stored DTCs are current enough and ensure that the troubleshooting is still needed. If the DTC is not active in the auto clear time, then the problem may not be still existing. In this case, a technician does not need to spend time to troubleshoot an old problem that has likely already been corrected or is not happening often enough to determine the root cause. All ECUs ( ECMs) store only limited number of unique DTCs in the memory. The limit is generally around 30 DTCs (15 diagnostics and 15 events) but vary by flash file. All the parameters of auto clear are fixed in the ECM flash file.
The auto clearing functionality is also required to ensure that the memory is not filled up with old data that could prevent new more relevant data from being stored. When memory allocated for logged events is full, a new event will not be stored as logged event. When memory allocated for diagnostics is full, a new logged diagnostic may overwrite existing logged diagnostics based on priority. Some ECM flash file configurations turn off the auto clear feature in order to store only predetermined number of logged DTCs in the ECM. Auto clearing of DTCs is common within our industries and other related industries.
Note: The automatic clear feature is available on all ECMs for all Caterpillar products listed above. However, some products may not have the capability to utilize it.
Note: For Tier 4 Engines and some Machines the critical DTCs [such as High Engine Coolant Temperature, Engine over speed and low engine oil pressure] will not Auto Clear. The rest of the DTCs will auto clear if the DTC is not active in the auto clear time.
Examples of Auto Clear configurations:
- Tier 3 Engine ECM (C15, C18, C27 & C32) is configured to delete logged DTCs if the logged DTCs do not become active within 100 SMH. Engine ECM has memory allocated to store up to 15 logged diagnostics and 15 logged events.
- Motor Grader (24M) Tier 3 Machine ECM is configured to delete logged diagnostics if the logged diagnostics do not become active within 150 SMH. Events do not auto clear. Machine ECM has memory allocated to store up to 20 logged diagnostics and 20 logged events.
- Track-Type Tractors (D10T & D11T) Tier 3 Machine ECM is configured to delete logged DTCs if the logged DTCs do not become active within 150 SMH. Machine ECM has memory allocated to store up to 20 logged diagnostics and 10 logged events.
Example Scenario in Tier 3 C15 Engine:
- An active "Engine Coolant Temperature Sensor : voltage above normal" diagnostic is deactivated at 700 SHM and stored as logged diagnostic at 700 SHM. The stored diagnostic is automatically cleared from logged diagnostics at 800 SHM, if the diagnostic does not become active between 700 to 800 SMH.
Different Methods to Acquire Operational Information
Some options for accessing recorded information from ECM when logged DTCs are deleted:
- Histograms
- Product Link
- VIMS
- Previous ECM Downloads
Histogram
 | |
| Illustration 1 | g03177594 |
Histogram (as stored in ECM) | |
Histograms provide frequency distributed data on engine and machine operation. Histograms provide information on operator efficiency, reduces time to troubleshoot some problems, and reduces unscheduled repairs by allowing trend analysis. Each histogram stored in the ECM is a set of counters. When the histogram parameter is sampled, the appropriate counter is incremented by one. Histograms are either two or three dimensional, number of counts vs. one or two parameters, respectively. All histograms with T4i or T4f software can be simultaneously reset (all the counters set back to zero) with factory passwords.
Engine overspeed and coolant temperature histograms can be used to check operating information. However, engine oil pressure history is not logged in ECM.
| Histograms for C11 – C32, 2005 and Up engines | ||||||
|---|---|---|---|---|---|---|
| Histogram Parameter (units) | Trap Conditions | Sample Period (secs) | Number of Counters (does not include underflow and overflow counters) | Minimum (units) | Width (units) | Histogram Type |
| 2 Dimensional (counts vs. one parameter) | 1 | |||||
| Engine (over) speed (rpm) | Engine speed > 2500 rpm | 8 | 2600 | 100 | occurrence | |
| Coolant temperature (°C) | Engine speed > 400 rpm, and at least 30 seconds since engine running | 14 | 50 | 5 | time | |
| Intake air temp (°C) | 1150 rpm < engine speed < 2250 rpm, and coolant temp > 75 °C, and fuel > 90% | 12 | 40 | 5 | time | |
| Boost pressure (KPa gauge) | 1150 rpm < engine speed < 2250 rpm, and coolant temp > 75 °C, and fuel > 90% | 12 | 80 | 10 | time | |
| 3 Dimensional (counts vs. two parameters) | ||||||
| Engine speed (rpm) | Engine speed > 400 rpm and coolant temp > 75 °C | 7 | 1000 | 200 | time | |
| Engine load at current engine speed (%) | 4 | 50 | 10 | time | ||
Note: The Engine (over) speed (rpm) histogram captures occurrences. But these occurrences, increment once every second. So the data displayed in this histogram is in seconds.
Product Link
Products with Product Link installed can track the DTC history in Equipment Manager or Vision Link. The DTC history is not erased and this DTC history gives the DTC occurrence date and the occurrence counts at each report. Product Link also tracks the hours and the reports containing time/date stamp to determine when the DTCs are reported.
VIMS
Products with VIMS installed can use the event chronological list to see the date/time and history of each DTC occurrence. This data can then be stored on a server or PC. This history does get erased from on-board when the data is downloaded.
ECM Downloads
Products with ET availability can use ECM downloads. There are two types of ECM downloads that can be used to store the DTCs, histograms, and other information about a product. The Warranty Report or Product Status Report (PSR) can be easily downloaded and stored in Service Information Management Systems (SIMSi). The warranty report does not contain all the histograms. By default, the PSR does not include the histograms. But you can get the histograms with the PSR if you select the appropriate option in Caterpillar Electronic Technician (Cat ET) while downloading the PSR.
Note: Dealers can get the instructions for downloading PSR from Cat ET page on https://dealer.cat.com.
Note: Previous uploaded ECM downloads can only be accessed from the SIMSi website by the dealer who uploaded the ECM downloads.
| Product Status Report showing Accumulated Time vs Engine Coolant Temperature | ||
|---|---|---|
| Engine Coolant Temperature (°C ) | Hours | Percentage % |
| <0.00 | 0.00 | 0.00 |
| 0.00-4.99 | 0.00 | 0.00 |
| 5.00-9.99 | 0.00 | 0.00 |
| 10.00-14.99 | 0.05 | 0.36 |
| 15.00-19.99 | 0.15 | 1.08 |
| 20.00-24.99 | 0.25 | 1.80 |
| 25.00-29.99 | 0.40 | 2.88 |
| 30.00-34.99 | 0.45 | 3.24 |
| 35.00-39.99 | 0.75 | 5.40 |
| 40.00-44.99 | 0.85 | 6.12 |
| 45.00-49.99 | 1.15 | 8.27 |
| 50.00-54.99 | 2.95 | 21.22 |
| 55.00-59.99 | 3.05 | 21.94 |
| 60.00-64.99 | 1.20 | 8.63 |
| 65.00-69.99 | 1.05 | 7.55 |
| 70.00-74.99 | 0.50 | 3.60 |
| 75.00-79.99 | 0.20 | 1.44 |
| 80.00-84.99 | 0.50 | 3.60 |
| 85.00-89.99 | 0.05 | 0.36 |
| 90.00-94.99 | 0.15 | 1.08 |
| 95.00-99.99 | 0.20 | 1.44 |
| 100.00-104.99 | 0.00 | 0.00 |
| 105.00-109.99 | 0.00 | 0.00 |
| 110.00-114.99 | 0.00 | 0.00 |
| 115.00-119.99 | 0.00 | 0.00 |
| 120.00-124.99 | 0.00 | 0.00 |
| 125.00-129.99 | 0.00 | 0.00 |
| 130.00-134.99 | 0.00 | 0.00 |
| 135.00-139.99 | 0.00 | 0.00 |
| 140.00-144.99 | 0.00 | 0.00 |
| 145.00-150.00 | 0.00 | 0.00 |
| >150.00 | 0.00 | 0.00 |