MBE 900 DDEC VI Troubleshooting – Section 18.7 Sensors

Section 18.7
Sensors

DDEC is designed to operate with several types of sensors as listed in Table "Sensor Types" .‪

Sensor Type‪	Description‪
Variable Reluctance/Magnetic Pick-up‪	Used to monitor the crankshaft position, engine speed, turbo speed, and vehicle speed.‪
Thermistor‪	Used to monitor temperatures.‪
Variable Capacitance‪	Used to monitor manifold, and oil gallery pressures.‪
Variable Resistance (Potentiometer)‪	Used to sense throttle position.‪
Switch‪	Used to signal coolant level.‪

The sensors integrated into the Engine Harness are factory-installed (refer to "18.7.1 Factory-installed Sensors" ). The sensors integrated into the Vehicle Interface Harness are installed by the OEM (refer to "18.7.2 OEM-installed Sensors" ).‪

Section 18.7.1
Factory-installed Sensors

The sensors integrated into the factory-installed Engine Harness are listed in Table "Function of Factory-installed Sensors" .‪

Sensor‪	Function‪
Camshaft Position Sensor (CMP Sensor)‪	Senses crankshaft position and engine speed for functions such as fuel control strategy.‪
Crankshaft Position Sensor‪ (CKP Sensor)‪	Indicates a specific cylinder in the firing order.‪
DPF Inlet Pressure Sensor‪	Sensor measures pressure on the outlet of the after-treatment device in the exhaust system of the vehicle. Located after the DPF that is within the after-treatment device.‪
DPF Outlet Pressure Sensor‪	Sensor measures pressure between the Diesel Oxidation Catalyst (DOC) and the Diesel Particulate Filter (DPF) in the after-treatment assembly located in the exhaust system of the vehicle.‪
DPF Outlet Temperature Sensor‪	Temperature measured at the outlet of the after-treatment system that is installed within the exhaust system of the vehicle. It's located after the DPF that is within the after-treatment unit.‪
DOC Inlet Temperature‪	Temperature measured at the inlet of the after-treatment device in the exhaust system of the vehicle. Located before the DOC that is within the after-treatment device.‪
DOC Outlet Temperature‪	Temperature measured between the DOC and the DPF in the after-treatment assembly located in the exhaust system of the vehicle.‪
EGR Delta Pressure Sensor‪ (EGR Delta P Sensor)‪	Senses EGR pressure for EGR control.‪
EGR Temperature Sensor‪	Senses EGR exhaust temperature after EGR cooler. Used for EGR system diagnosis.‪
Engine Coolant Temperature Sensor (ECT Sensor)‪	Senses coolant temperature for functions such as engine protection, fan control and engine fueling.‪
Engine Oil Pressure Sensor‪ (EOP Sensor)‪	Senses gallery oil pressure for functions such as engine protection.‪
Engine Oil Temperature Sensor (EOT Sensor)‪	Senses oil temperature for functions such as reducing variation in fuel injection and fan control.‪
Fuel Line Pressure Sensor‪	Senses fuel line pressure‪
Fuel Compensation Pressure Sensor‪	Compensates fuel line pressure‪
Intake Manifold Pressure Sensor (IMP Sensor)‪	Senses turbo boost for functions such as smoke control and engine protection.‪
Intake Manifold Temperature Sensor (IMT Sensor)‪	Senses boost temperature‪
Supply Fuel Temperature Sensor (SFT Sensor)‪	Senses fuel temperature for functions such as engine fueling.‪
Turbo Compressor Temperature Out Sensor‪	Senses turbo out air temperature.‪
Turbo Speed Sensor‪	Monitors turbo speed.‪
Water-in-Fuel Sensor‪ (MBE 900 and Heavy-Duty Series Engine)‪	Detects water in the fuel filter that alerts the owner/driver that the fuel filter needs to be dried out.‪

See Figure "Sensor Location for the DOC and DPF" for the location of the sensors for the DOC and DPF.‪

Figure 1. Sensor Location for the DOC and DPF

Section 18.7.2
OEM-installed Sensors

All sensors must be of the proper type and continuously monitor vehicular and environmental conditions, so the MCM can react to changing situations.‪

The OEM is responsible for installing the sensors listed in Table "Function and Guidelines for OEM-installed Sensors" .‪

Sensor‪	Part Number‪	Function‪
Ambient Air Temperature Sensor‪ (AAT Sensor)‪	23518328‪	Senses ambient air temperature specifically for the Ambient Air Temperature Override Disable feature or for OI. Refer to "18.7.3 Ambient Air Temperature Sensor" .‪
Engine Coolant Level Sensor (ECL Sensor)‪	23526906‪ 23526905‪ 23526907‪	Senses coolant level for engine protection. Refer to "18.7.4 Engine Coolant Level Sensor" .‪
Turbo Compressor In Temperature Sensor‪	23527831‪	Senses the temperature of the turbo compressor inlet.‪ Refer to "18.7.5 Turbo Compressor In Temperature Sensor" .‪
Vehicle Speed Sensor (VSS)‪	-—‪	Senses vehicle speed for Cruise Control and Vehicle Speed Limiting. Refer to "18.7.6 Vehicle Speed Sensor" .‪

* Available in some applications

Note: The OEM harness must be securely fastened every six (6) in. It is required that the harness be fastened within six (6) in. of the sensor.

Section 18.7.3
Ambient Air Temperature Sensor

The AAT Sensor is a thermistor type sensor with a variable resistance that produces an analog signal between 0 and 5 V, representing the temperature of the ambient air. The AAT Sensor is used with the Idle Shutdown Timer, specifically for the Ambient Air Temperature Override Disable feature or for Optimized Idle. ‪

Note: This sensor is optional.

Install the AAT Senaor where ambient air temperature can be read. A protected location on the frame rails where it will not be splattered with dirt and grime and is removed from any heat source such as exhaust is preferred. See Figure "Ambient Air Temperature Sensor Installation" for AAT Sensor installation.‪

Figure 2. Ambient Air Temperature Sensor Installation

Section 18.7.4
Engine Coolant Level Sensor

The ECL Sensor provides an input to the engine protection system and warn the operator if a low coolant level has been reached.‪

The main component of the ECL Sensor consists of a conductivity probe, which connects to the CPC (see Figure "Engine Coolant Level Sensor Specifications" ).‪

NOTICE:
The probe has an operational temperature range of -40 to 257°F (-40 to 125°C). Exposure to temperatures beyond this range may result in unacceptable component life, or degraded sensor accuracy.‪

Figure 3. Engine Coolant Level Sensor Specifications

‪

The connector listed in Table "Metri-Pack 280 Connectors and Part Numbers" is a Metri-Pack 280 series push-to-seat connector. ‪

Coolant Level Sensor Connector‪
Connector‪	P/N: 15300027‪
Terminal‪	P/N: 12077411‪
Seal‪	P/N: 12015323‪
Secondary Lock‪	P/N: 15300014‪

The OEM must connect the ECL Sensor probe as shown in the next illustration (see Figure "Engine Coolant Level Sensor Installation for CPC" ). Polarity of the ground and signal must be correct for proper operation. ‪

Figure 4. Engine Coolant Level Sensor Installation for CPC

The probe should be located in either the radiator top tank or a remote mounted surge tank. It should be mounted horizontally in the center of the tank and must be in a position to signal low coolant before aeration occurs. Typically, this is a height representing 98% of the drawdown quantity. The probe should be located so that it is not splashed by deaeration line, stand pipe or coolant return line flows. The insulated portion of the probe should be inserted into the coolant 1/2 in. or more past the inside wall of the tank. See Figure "Engine Coolant Level Sensor Location - Top of Radiator Tank" .‪

Figure 5. Engine Coolant Level Sensor Location - Top of Radiator Tank

‪

Determine proper location for low coolant level sensor while running the drawdown test. It must actuate a warning before the satisfactory drawdown level is reached.‪

The ECL Sensor components are OEM supplied hardware and can be purchased as kits or individual components, depending on OEM requirements.‪

The sensor must be enabled with VEPS or the DRS as listed in Table "Enabling the Engine Coolant Level Sensor" .‪

Parameter‪	Options‪	Default‪
Cool Level Sensor Input Enable‪	0 = Disabled‪ 1 = Dual Level Probe Sensor (IMO)‪ 2 = Single Level Probe Sensor‪ 3 = Dual Level Float Sensor (FTL)‪	2‪

Section 18.7.5
Turbo Compressor In Temperature Sensor

The Turbo Compressor In Temperature Sensor (TCI Sensor) produces a signal representing the temperature of the turbo compressor inlet. See Figure "Turbo Compressor In Temperature Sensor" .‪

Figure 6. Turbo Compressor In Temperature Sensor

This sensor is required for the Series 60.‪

The maximum vibration for the sensor is 5 g. The sensor must be torqued between 10 ft lb and 20 ft lb. The harness must be fastened within 6 in of the sensor. The maximum operating temperature for this sensor is 248°F (120°C).‪

Install the Turbo Compressor In Temperature Sensor in the filtered air side of the air filter canister. Otherwise it must be mounted between the air cleaner and the turbocharger compressor inlet. This sensor has a pigtail on the Engine Harness. It it does not fit your application, this circuit is also available in the 31–pin Engine Harness connector. The OEM is responsible for wiring this sensor to either location.‪

Section 18.7.6
Vehicle Speed Sensor

The CPC can calculate vehicle speed providing that it is properly programmed and interfaced with a Vehicle Speed Sensor (VSS) that meets requirements. The VSS (see Figure "Vehicle Speed Sensor" ) provides a vehicle speed signal for use in Cruise Control and Vehicle Speed Limiting. The VSS signal type can be changed v‪

Note: DDC does not approve of the use of signal generator sensors.

Figure 7. Vehicle Speed Sensor

To obtain accurate vehicle mileage, the parameters listed in Table "Vehicle Speed Sensor Parameters" must be programmed with VEPS, DRS, or DDDL 7.0.‪

Parameter‪	Range‪	Default‪
Vehicle Speed Sensor‪	0 = No Sensor‪ 1 = C3 Sensor‪ 2 = Square Wave (Hall Sensor)‪ 3 = Vehicle Speed over J1939 (ECT1)‪ 4 = Magnetic Pickup‪ 5 = Vehicle Speed via J1939 (TCO1, SPN 1624)‪ 8 = Vehicle Speed via J1939 (CCVS, SPN 84)‪	4 = Magnetic‪
Axle Ratio‪	1 – 20.0‪	5.29‪
Number of Output Shaft Teeth‪	0 – 250‪	16‪
Tire Revs per Unit Distance‪	160 – 1599‪	312‪
Top Gear Ratio‪	0.1 – 2.55‪	1‪
Second Highest Gear Ratio‪	0.1 – 2.55‪	1‪
Two Spd Axle Second Axle Ratio‪	1 – 20.0‪	5.29‪
Anti Tamper‪	0 = Disable‪ 1 = Enable VSS ABS Anti Tampering Function‪ 2 = Enable VSS without ABS Anti Tampering Function‪	0 = Disable‪

Section 18.7.6.1
Magnetic Pickup

The magnetic pickup requirements are listed in Table "Magnetic Pickup Vehicle Speed Sensor Requirements" . Magnetic Pickup size is determined by installation requirements. ‪

Parameters‪	Range‪
Frequency Range‪	0 - 10 kHz‪
Low Threshold Voltage‪	>1.8 Volts Peak to Peak‪

The Vehicle Speed Sensor is wired to the 21–pin #3 connector of the CPC as listed in Table "Vehicle Speed Sensor Wiring" .‪

CPC Connector/Pin‪	Function‪
3/13‪	VSS (+)‪
3/14‪	VSS (-)‪

See Figure "Magnetic Vehicle Speed Sensor Installation – CPC" for the installation of the Magnetic VSS.‪

Figure 8. Magnetic Vehicle Speed Sensor Installation – CPC

Section 18.7.6.2
SAE J1939 Data Link

A VSS wired to the CPC is not required if the transmission output shaft speed message is being transmitted over the SAE J1939 Data Link. To obtain accurate vehicle mileage, the parameters listed in Table "Vehicle Speed Sensor Parameters for Transmission Output Shaft Speed" must be programmed with VEPS. ‪

Parameter‪	Range‪		Default‪
Vehicle Speed Sensor‪	0 = No Sensor‪ 1 = C3 Sensor‪ 2 = Square Wave (Hall Sensor)‪ 3 = Vehicle Speed over J1939‪ 4 = Magnetic Pickup‪ 5 = Vehicle Speed via J1939 (TCO1, SPN 1624)‪ 8 = Vehicle Speed via J1939 (CCVS, SPN 84)‪		4 = Magnetic‪
Axle Ratio‪	1 – 20.0‪		5.29‪
Tire Revs per Unit Distance‪	160 – 1599‪		312‪
Top Gear Ratio‪	0.1 – 2.55‪		1‪
Second Highest Gear Ratio‪	0 — 5.75‪		2.55‪
Two Spd Axle Second Axle Ratio‪	1 – 20.0‪		5.29‪
Anti Tamper‪	0 = Disable‪ 1 = Enable VSS ABS Anti Tampering Function‪ 2 = Enable VSS without ABS Anti Tampering Function‪		0 = Disable‪

Section 18.7.6.3
VSS Anti-tamper

If the sensor appears to be working improperly, but the vehicle speed is not zero, VSS Anti-Tamper will log a VSS fault.‪