Wiring for the Exhaust Temperature Module
Wiring for the Power Supply
The range for the input voltage is 10 to 32 VDC. A 12 volt supply or a 24 volt supply can be used.
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| Illustration 1 | g01473696 |
Connections for the CAN data link | |
In petroleum or industrial applications, the exhaust temperature module communicates with the advisor monitor display over the SAE J1939 CAN data link. In these applications, the CAN data link must be connected to the exhaust temperature module at pins 5, 8, and 9. Refer to Illustration 1.
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| Illustration 2 | g01473713 |
(1) 133-8751 Receptacle As (2) 251-9430 Exhaust Temperature Module (3) 251-9428 Bracket As (4) 292-8601 Bracket As | |
Note: Use the 251-9428 Bracket As with G3500 engines. Use the 292-8601 Bracket As with 3500 diesel engines.
Wiring for the Thermocouples
Channels that are Connected to Thermocouples
Note: All of the wiring for the thermocouples must be type K.
The exhaust temperature module has a channel for each thermocouple. For example, channel 1 represents the number 1 cylinder. The wiring from each thermocouple is connected to the terminals for the corresponding channel. Channels 21 through 24 are used for the thermocouples for turbochargers.
The cable for the thermocouples has a pair of wires inside the insulation: one of the wires is yellow and one of the wires is red. The yellow wire is the positive wire for a thermocouple. the red wire is the negative wire for the thermocouple. The polarity of the wires must be maintained or the readings will be incorrect. Table 1 lists the connections for thermocouples for various engines. Table 2 lists a description for the remaining pins on the 70-pin connector.
| Pin Identification for the Thermocouples on the 70-pin Connector | |||||
|---|---|---|---|---|---|
| Channel No. |
Pin No. |
Description | 3508 G3508 |
3512 G3512 |
3516 G3516 |
| 1 | 1 | Positive wire for thermocouple 1 | Cyl 1 | Cyl 1 | Cyl 1 |
| 2 | Negative wire for thermocouple 1 | ||||
| 2 | 3 | Positive wire for thermocouple 2 | Cyl 2 | Cyl 2 | Cyl 2 |
| 4 | Negative wire for thermocouple 2 | ||||
| 3 | 14 | Positive wire for thermocouple 3 | Cyl 3 | Cyl 3 | Cyl 3 |
| 15 | Negative wire for thermocouple 3 | ||||
| 4 | 16 | Positive wire for thermocouple 4 | Cyl 4 | Cyl 4 | Cyl 4 |
| 17 | Negative wire for thermocouple 4 | ||||
| 5 | 24 | Positive wire for thermocouple 5 | Cyl 5 | Cyl 5 | Cyl 5 |
| 25 | Negative wire for thermocouple 5 | ||||
| 6 | 26 | Positive wire for thermocouple 6 | Cyl 6 | Cyl 6 | Cyl 6 |
| 27 | Negative wire for thermocouple 6 | ||||
| 7 | 32 | Positive wire for thermocouple 7 | Cyl 7 | Cyl 7 | Cyl 7 |
| 33 | Negative wire for thermocouple 7 | ||||
| 8 | 34 | Positive wire for thermocouple 8 | Cyl 8 | Cyl 8 | Cyl 8 |
| 35 | Negative wire for thermocouple 8 | ||||
| 9 | 40 | Positive wire for thermocouple 9 | Shorted | Cyl 9 | Cyl 9 |
| 41 | Negative wire for thermocouple 9 | ||||
| 10 | 42 | Positive wire for thermocouple 10 | Shorted | Cyl 10 | Cyl 10 |
| 43 | Negative wire for thermocouple 10 | ||||
| 11 | 48 | Positive wire for thermocouple 11 | Shorted | Cyl 11 | Cyl 11 |
| 49 | Negative wire for thermocouple 11 | ||||
| 12 | 50 | Positive wire for thermocouple 12 | Shorted | Cyl 12 | Cyl 12 |
| 51 | Negative wire for thermocouple 12 | ||||
| 13 | 10 | Positive wire for thermocouple 13 | Shorted | Shorted | Cyl 13 |
| 11 | Negative wire for thermocouple 13 | ||||
| 14 | 12 | Positive wire for thermocouple 14 | Shorted | Shorted | Cyl 14 |
| 13 | Negative wire for thermocouple 14 | ||||
| 15 | 20 | Positive wire for thermocouple 15 | Shorted | Shorted | Cyl 15 |
| 21 | Negative wire for thermocouple 15 | ||||
| 16 | 22 | Positive wire for thermocouple 16 | Shorted | Shorted | Cyl 16 |
| 23 | Negative wire for thermocouple 16 | ||||
| 17 | 28 | Positive wire for thermocouple 17 | Shorted | Shorted | Shorted |
| 29 | Negative wire for thermocouple 17 | ||||
| 18 | 30 | Positive wire for thermocouple 18 | Shorted | Shorted | Shorted |
| 31 | Negative wire for thermocouple 18 | ||||
| 19 | 36 | Positive wire for thermocouple 19 | Shorted | Shorted | Shorted |
| 37 | Negative wire for thermocouple 19 | ||||
| 20 | 38 | Positive wire for thermocouple 20 | Shorted | Shorted | Shorted |
| 39 | Negative wire for thermocouple 20 | ||||
| 21 | 44 | Positive wire for thermocouple 21 | Left Turbo Inlet (1) | Left Turbo Inlet | Left Turbo Inlet |
| 45 | Negative wire for thermocouple 21 | ||||
| 22 | 46 | Positive wire for thermocouple 22 | Left Turbo Outlet (1) | Left Turbo Outlet | Left Turbo Outlet |
| 47 | Negative wire for thermocouple 22 | ||||
| 23 | 54 | Positive wire for thermocouple 23 | Right Turbo Inlet | Right Turbo Inlet | Right Turbo Inlet |
| 55 | Negative wire for thermocouple 23 | ||||
| 24 | 56 | Positive wire for thermocouple 24 | Right Turbo Outlet | Right Turbo Outlet | Right Turbo Outlet |
| 57 | Negative wire for thermocouple 24 | ||||
| ( 1 ) | Shorted for engines with a single turbocharger |
| Pin Identification of the Remaining pins on the 70-pin Connector | |
| Pin Number | Description |
| 5 | CAN Shield |
| 6 | Power + |
| 7 | Power - |
| 8 | CAN (+) |
| 9 | CAN (-) |
| 18 | Not Connected |
| 19 | Not Connected |
| 52 | Not Connected |
| 53 | Not Connected |
| 58 | Output Switch 2 (-) |
| 59 | Output Switch 2 (+) |
| 60 | Output Switch 1 (+) |
| 61 | Output Switch 1 (-) |
| 62 | Rotation Sensor |
| 63 | Spare Input |
| 64 | Not Connected |
| 65 | N/A |
| 66 | Shield (Data) (RS-485) |
| 67 | N/A |
| 68 | N/A |
| 69 | Data (+) (RS-485) |
| 70 | Data (-) (RS-485) |
Take care not to damage the insulation during installation. Take precautions against later damage from vibration, abrasion, pinch points, and liquids in conduits. Additionally, it is essential to use the following practices:
- Keep high voltage wiring at least 30 cm (12 inch) away from the thermocouples and the wiring for the thermocouples. Never wire thermocouples with any other wiring from sources of high power.
- For spark ignited engines, never wire thermocouples through the same conduit as the ignition wiring. Use spark plugs with resistors for lower electromagnetic interference (EMI). Install the thermocouples at least 30 cm (12 inch) away from wiring for the ignition.
Avoid any additional junctions and/or splices in order to ensure that an accurate signal is transmitted to the exhaust temperature module.
Unused Channels
The exhaust temperature module is capable of monitoring 24 channels. The exhaust temperature module is self-diagnostic. In order to avoid false diagnostics for the unused channels, the unused channels must be shorted. Do not wire the unused channels into the harness.
For example, an eight cylinder engine with one turbocharger will typically use ten channels. Eight of the channels are used for thermocouples at the cylinder exhaust ports. One of the channels is used for the exhaust inlet to the turbocharger. The tenth channel is used for the exhaust outlet from the turbocharger. The remaining channels are not used.
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| Illustration 3 | g01473737 |
Example of a jumper wire for an unused channel | |
Refer to Illustration 3. Crimp a 186-3736 Connector Socket onto each end of a jumper wire. Install the jumper wire onto the appropriate pins for each channel that is not used.
Alarm for "Deviation from Average"
The Society of Automotive Engineers inc. (SAE) does not have a Parameter Group Number (PGN) or Suspect Parameter Number (SPN) for "Deviation from Average". Caterpillar is using "Exhaust Gas Temperature" in order to represent "Average Cylinder Temperature". The PGN is 65270. The SPN is 173.
Testing the Circuits for the Thermocouples
Disconnect the wiring for a thermocouple from the exhaust temperature module before you test the wiring with an ohmmeter or another instrument. This will prevent possible damage to the exhaust temperature module's sensitive circuitry.
Wiring for the Output Switches
The exhaust temperature module contains two solid state output switches. Each output switch is rated for a maximum of 2 amperes at 35 VDC. The default configuration of each output switch is normally open.
The output switches can be wired in order to activate alarms or shutdowns. For example, the number 1 output switch can be wired for an alarm and the number 2 output switch can be wired for a shutdown.
Refer to Table 3 for identification of the pins for the output switches.
| Pins for the Output Switches | ||
|---|---|---|
| Pin | Output Switch | Function |
| 58 | 2 | Return |
| 59 | Output | |
| 60 | 1 | Output |
| 61 | Return | |
Refer to Illustration 4 for an example of the wiring for the output switches. In this example, the outputs are used to control relays.
Note: Flyback diode protection for the two output switches is built into the ETM circuit board.
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| Illustration 4 | g01473757 |
Example of the wiring for the output switches | |
Input for Engine Rotation
Pin 62 is the input for engine rotation. Typically, this input is not used. When this input is not used, the circuit must be open. When the circuit is open, all of the setpoints are active. It is important for this circuit to be open during normal engine operation. Refer to Testing and Adjusting, "Start-up Sequence".
When this input is connected to ground, all of the setpoints and the output switches are deactivated. Therefore, the engine is not protected against problems with exhaust temperatures.
If this input is used, an open circuit indicates that the engine is running. An external contact must be provided in order to open the circuit when the engine is running. The external contact must ground the circuit when the engine is stopped.
Completing the Installation of the Wiring
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| Illustration 5 | g01473793 |
Connecting the electrical connector for the exhaust temperature module (5) 160-7689 Connector Plug As (6) Bolt | |
Connector (5) is secured to the exhaust temperature module with captive bolt (6). The bolt is tightened to a torque of 6 ± 1 N·m (53 ± 9 lb in).
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| Illustration 6 | g01308427 |
The connector cover for applications that are not Canadian Standards Association (CSA) certified. (5) 160-7689 Connector Plug As (7) 126-1774 Cover | |
Protect the pins in connector (5) by installing cover (7).
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| Illustration 7 | g01476514 |
The connector cover for applications that are CSA certified. (8) 288-4678 Connector As (9) 232-4674 Connector Seal (10) 288-4677 Connector As (11) 232-4675 Connector Seal | |