U017F Lost Communication With Belt Pretensioner Module B

U017F Lost Communication With Belt Pretensioner Module B

OBD-II DTC Datasheet

Lost Communication With Seat Belt Pretensioner Module B

What does this mean?

This is a generic communications system diagnostic trouble code that applies to most makes and models of OBD-II vehicles.

This code means that the seat belt pretensioner module B (SBPM-B) and other control modules on the vehicle are not communicating with each other. The circuitry most commonly used for communication is known as Controller Area Bus communication, or simply the CAN bus.

Modules communicate with each other over a network, just like the network you have at home or work. Car manufacturers use several networked systems. Prior to 2004, the most common (non-exhaustive) inter-module communication systems were the serial communication interface, or SCI; SAE J1850 or PCI bus; and Chrysler Collision Detection, or CCD. The most common system used after 2004 is known as Controller Area Network communication, or simply the CAN bus (also used until 2004 on a small segment of vehicles). Without this CAN bus, control modules cannot communicate and your scan tool may or may not receive information from the vehicle, depending on which circuit is affected.

The seat belt pretensioner module B (SBPM-B) is usually located behind the dashboard, usually in the center of the vehicle, although in some vehicles it may be installed on the B-pillars. It receives input from a variety of sensors, some of which are directly connected to it, and most are sent over a bus communication system from the powertrain control module (PCM). The most important of these sensor inputs are the collision or collision sensors. This input allows the module to determine when a collision has occurred or when the vehicle is simply slowing down quickly. The difference between the two is that the SBPM-A can take no action or can activate the seat belt pretensioners. It can send data to the restraint control module to inform it of a side impact.

Troubleshooting steps may vary depending on the manufacturer, the type of communication system, the number of wires, and the colors of the wires in the communication system.

Code severity and symptoms

The severity in this case is always serious due to the safety issues that arise in a non-functional restraint control system. Safety is ANYONE's concern when you service these systems because they can continue to operate even when the warning lights are on. ALWAYS treat these systems as if they could work at any time.

Symptoms of a U017F code may include:

• Airbag light is on or flashing

reasons

Usually the reason for installing this code is:

• Open on CAN bus + or - circuit
• Short to ground or ground in any CAN bus circuit
• No power or ground to SBPM-B module
• Rarely - the control module is faulty

Diagnostic and repair procedures

A good place to start with ALL electrical diagnostics is to check the Technical Service Bulletins (TSB) for your vehicle. The problem you are facing may be known to others in the field. A known fix may have been released by the manufacturer and can save you time and money during diagnostics.

It is assumed that you have access to a code reader at this point, as you may have been able to access the codes up until now. See if there were any other DTCs related to bus communication or battery / ignition. If so, you should diagnose them first, as a misdiagnosis is known to occur if you diagnose the U017F code before any of the underlying codes are thoroughly diagnosed and corrected.

If the only code you get from other modules is U017F, try accessing SBPM-B. If you can access codes from SBPM-B, then code U017F is either intermittent or memory code. If the SBPM-B cannot be accessed, then code U017F set by other modules is active and the problem already exists.

The most common fault is a circuit fault that cuts power or ground to the pretensioner module b.

Check all fuses supplying the SBPM-B module on this vehicle. Check all grounds for SBPM-B. Locate ground anchorage points on the vehicle and make sure these connections are clean and secure. If necessary, remove them, take a small wire bristle brush and baking soda / water solution and clean each one, both the connector and the place where it connects.

If any repairs have been made, clear the DTCs from all modules that set the code in memory and see if you can now communicate with the SBPM-B module. If communication with SBPM-B recovers, the problem is most likely a fuse / connection issue.

BEFORE DISCONNECTING THE MODULE CONNECTORS, MAKE SURE THE SYSTEM IS TURNED OFF ACCORDING TO THE MANUFACTURER'S PROCEDURES! Otherwise, POSSIBLE DAMAGE TO THE VEHICLE OR PERSONAL INJURY DUE TO UNINTENDED DEPLOYMENT OF THE AIR BAG. ALSO, THE AIRBAGS ARE DISCONNECTED DURING THE FOLLOWING TESTS AS A FINAL SAFETY MEASURE!

If the code returns or communication still cannot be established with the module, locate the CAN bus communication connections on your vehicle, most importantly the SBPM-B connector, which is usually located behind the dashboard, usually in the center of the vehicle, albeit at on some vehicles, it can be installed on the B-pillars. Disconnect the negative battery cable before disconnecting the connector on the SBPM-B. Once detected, visually inspect the connectors and wiring. Look for scratches, scuffs, exposed wires, burn marks, or molten plastic.

Disconnect the connectors and carefully inspect the terminals (metal parts) inside the connectors. See if they look burnt or have a green tint indicating corrosion. If you need to clean the terminals, use an electrical contact cleaner and a plastic bristle brush. Allow to dry and apply electrical grease where the terminals touch.

Perform these few voltage checks before reconnecting the connectors to the SBPM-B. You will need access to a digital volt/ohmmeter (DVOM). Make sure the SBPM-B has power and ground. Access the wiring diagram and determine where the main powers and grounds enter the SBPM-B. Connect the battery before continuing with the SBPM-B still disconnected. Connect the red lead of your voltmeter to each B+ (battery voltage) power supply included in the SBPM-B connector, and the black lead of your voltmeter to a good ground (if unsure, battery negative always works). You should see the battery voltage reading. Make sure you have a good reason. Connect the red lead of the voltmeter to the battery positive (B+) and the black lead to each ground circuit. Once again, you should see the battery voltage every time you connect. If not, repair the power or ground circuit.

Then check the two communication circuits. Locate CAN C+ (or HSCAN+) and CAN C- (or HSCAN - circuit). With the black wire of the voltmeter connected to a good ground, connect the red wire to CAN C+. With the key on and engine off, you should see about 2.6 volts with little fluctuation. Then connect the red wire of the voltmeter to the CAN C- circuit. You should see about 2.4 volts with little fluctuation. Other manufacturers show CAN C- at about 5V and an oscillating key with the engine off. Check your manufacturer's specifications.

If all tests pass and communication is still not possible, or you were unable to reset DTC U017F, the only thing to do is to seek help from a trained automotive diagnostician, as this will indicate a SBPM-B failure. . Most of these SBPM-Bs must be programmed or calibrated in order to properly install the vehicle.

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