DD15 ECM Location: A Guide for Diesel Mechanics

The DD15 is a popular heavy-duty diesel engine manufactured by Detroit Diesel. It is used in various applications such as trucks, buses, and construction equipment. The DD15 engine has an electronic control module (ECM) that manages the engine’s performance, emissions, and diagnostics. The ECM is a vital component that needs to be serviced and maintained regularly.

What is the ECM and what does it do?

The ECM is a computer that monitors and controls the engine’s operation. It receives input signals from various sensors and actuators, and sends output signals to control the fuel injection, turbocharger, exhaust gas recirculation (EGR), aftertreatment, and other systems. The ECM also stores fault codes and diagnostic information that can be accessed by a scan tool.

The ECM has two main parts: the motor control module (MCM) and the common powertrain controller (CPC). The MCM is responsible for the engine management, while the CPC is responsible for the vehicle interface and communication. The MCM and the CPC are connected by a 21-pin connector. The MCM also has a 120-pin connector that connects to the engine harness. The ECM also communicates with the aftertreatment control module (ACM), which is located near the emission control equipment.

Where is the ECM located and how to access it?

The ECM is mounted in the engine compartment, above the driver-side inner fender. To access the ECM, you need to remove the hood and the air cleaner assembly. You also need to disconnect the batteries and the ECM connectors before removing the ECM. The ECM is secured by four bolts and a bracket. You need to use a torque wrench to tighten the bolts to the specified torque when reinstalling the ECM.

The following table shows the pinout of the 120-pin connector of the MCM:

Pin Function Connector
1 Quality Control Valve
2 Quality Control Valve
3 NC
4 Spill Amplifier Control Valve (cyl 4) – pin 2
5 NC
6 Spill Amplifier Control Valve (cyl 6) – pin 2
7 Spill Amplifier Control Valve Common (cyl 4, 5, 6) – pin 1
8 Spill Amplifier Control Valve (cyl 5) – pin 2
9 NC
10 Spill Amplifier Control Valve (cyl 2) – pin 2
11 NC
12 Spill Amplifier Control Valve (cyl 3) – pin 2
13 Spill Amplifier Control Valve Common (cyl 1, 2, 3) – pin 1
14 Spill Amplifier Control Valve (cyl 1) – pin 2
15 NC
16 Needle Control Valve (cyl 4) – pin 4
17 NC
18 Needle Control Valve (cyl 6) – pin 4
19 Needle Control Valve Common (cyl 4,5,6) – pin 3
20 Needle Control Valve (cyl 5) – pin 4
21 NC
22 Needle Control Valve (cyl 2) – pin 4
23 NC
24 Needle Control Valve (cyl 3) – pin 4
25 Needle Control Valve Common (cyl 1,2,3) – pin 3
26 Needle Control Valve (cyl 1) – pin 4
27 NC
28 NC
29 DOC Outlet Temp Sensor
30 DPF Outlet Pressure Sensor
31 NC
32 Jake 1
33 Two-speed Fan or Variable Speed Fan
34 NC
35 NC
36 NC
37 NC
38 Ground
39 NC
40 NC
41 Grid Heater
42 NC
43 CKP/TRS (+)
44 NC
45 CMP/SRS (+)
46 NC
47 Fan Speed
48 CMP/SRS (-)
49 NC
50 Sensor Ground
51 Turbo Speed Sensor
52 Sensor Ground
53 NC
54 Sensor Ground
55 Sensor Ground
56 NC
57 Water-in-Fuel-Sensor
58 Sensor Power Supply
59 HDMS Fan Thermal Switch
60 EGR Valve Position

How much does the ECM cost and where to buy it?

The ECM is a costly and sensitive part that should be handled with care. The price of a new ECM can range from $2,000 to $4,000, depending on the model and the supplier. A used or remanufactured ECM can be cheaper, but it may not be compatible or reliable. You should always check the part number, serial number, and calibration code of the ECM before buying it.

You can buy the ECM from authorized Detroit Diesel dealers or online vendors. Some of the online vendors that sell DD15 ECMs are:

  • Heavy Truck Parts: This website offers a wide range of used and rebuilt ECMs for various models of Detroit Diesel engines. You can search by part number, model, or keyword. The price of a DD15 ECM on this website ranges from $800 to $2,000, depending on the condition and availability.
  • Vander Haag’s: This website sells new and used heavy-duty truck parts, semi truck salvage, trucks, trailers, equipment, and service. You can find DD15 ECMs for sale on this website by searching by manufacturer, model, and part type. The price of a DD15 ECM on this website ranges from $915 to $2,118, depending on the year and condition.
  • My Little Salesman: This website is a marketplace for buying and selling new and used heavy equipment, trucks, trailers, and parts. You can find DD15 ECMs for sale on this website by searching by category, manufacturer, model, and location. The price of a DD15 ECM on this website is $1,099.99, as of February 2024.
  • Diesel ECM: This website specializes in diesel engine control modules and offers repair, exchange, and programming services. You can buy a DD15 ECM from this website by selecting the part number and filling out the order form. The price of a DD15 ECM on this website is $1,295, as of February 2024.
  • Vander Haag’s: This website sells new and used heavy-duty truck parts, semi truck salvage, trucks, trailers, equipment, and service. You can buy a DD15 ECM from this website by selecting the part number and adding it to the cart. The price of a DD15 ECM on this website is $915, as of February 2024.

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