VISION 2015
Presents….
By: Al San1ni ConsuLab
Teaching The theory and Diagnosis of a Mul>ple CAN System “Mostly”
at the DLC
WHO AM I?
• Al San>ni • Taught technicians for years at CC level
• Former electrical and emission instructor at College of DuPage
• Independent Trainer now with ConsuLab
• alsan>[email protected]
What are we going to do? • Generalize CAN as a communica>on thingy • Discuss requirements of equipment • Go thru typical low speed • Go thru typical high speed • Go thru both types of mul>ple CAN • Show basic diagnos>c tes>ng at the DLC and/or module
– DMM – DSO
• Look at some typical LIN (linear interconnect network) • Give you something you may be able to use tomorrow • Think, discuss, digest, BS and learn…. • Keep track of what you do and when….
Some “Pre” Thoughts • CAN is here to stay. Virtually all 2008+ • Mul>ple high speed CAN on many 2010+ • CAN is a source of frequent MIL on (emission failures?) • CAN is a source of frequent DTC’s (“U” Codes) • You MUST understand the basics or you will be screwed !! • You MUST have equipment to communicate with a CAN
equipped vehicle • You MUST have up-‐to-‐date scanner sobware to
communicate with a CAN equipped vehicle • You MUST have access to a communica>ons wiring
diagram
What is CAN ?? • Controller Area Network (CAN)
– Local communica>on similar to connec>ng various devices along an Ethernet
• Linear Interconnect Network (LIN) – New to the network (2011 ish)
• Defini>ons: – Gateway = the device that communicates with the “outside” world and between mul>ple CAN Networks
– Bus = a big rolling device that carries people – Bus = the connec>on between devices – Termina>on = usually the two ends of the system – Wake-‐up = a signal sent out by the gateway to begin communica>on
– Roll-‐call = the gateway asks “Are you here and do you have problems?”
History (stay awake….) • 1983 Bosch introduces CAN (on paper) • 1987 protocol released • 1987 first CAN chips made by Intel • Aber ‘87 CAN (called Mul>plex) starts to show up • 1996 CAN becomes one of OBD-‐II protocols • By 2008 virtually everything is CAN (even trucks !!) • Low speed CAN up to 125Kbits/sec (125,000) • High speed CAN up to 1Mbit/sec (1,000,000) • 8 >mes faster…. And we are not done • Flexray (BMW 8X) up to 10Mbit/sec (10,000,000) • Or 80 >mes faster than low speed • Future???
So… What Is Important? • Communica>on errors are the
most common -‐ U codes • Different protocols • Single wire vs two wire • Low speed vs High speed • Mul>ple high speed CAN
networks becoming common • LIN becoming more common • Equipment requirements • Wiring diagram details • Simple diagnos>c procedure
Demo….
• I am the gateway • 5 modules in network • Wake-‐up • Roll call • Problems? • Analysis and communica>on with outside world
Check the Diagram….
All Data would be proud
Gateway Ques>ons
• Wake up • Roll call
– SIR – PCM – TCM – An>-‐lock
• Problems (DTC’s)
1St Example
• During roll call • Each module answered “here with no DTC’s” • What does this mean?
– Communica>on is possible along Bus – Modules are present and communica>ng – No module has any problems
• You will seldom see this example on a vehicle with MIL on
2nd Example
• SIR = Here and communica>ng with no DTC’s • An>-‐Lock = here and communica>ng with 1 DTC – We need to look at the DTC – duh….
• TCM = here and communica>ng with the gateway but no one else
• PCM = here and communica>ng and “seeing” problems with other modules
3rd Example
• SIR = no communica>on and not on line • An>-‐Lock = no communica>on and not on line • TCM = no communica>on and not on line • PCM = no communica>on and not on line • Odds are the communica>on bus is down
– Vehicle probably dead… – There may be hidden DTC’s – Get the CAN Bus up and re-‐scan – Tough to es>mate cost
Conclusion and Choices
• Each module should be able to: – Communicate
• To both the Gateway and each other to share informa>on
– Indicate DTC’s – Indicate if it is not on line (How? By NOT waking up)
• Only accomplished if the CAN Bus is func>oning correctly
What is the Gateway here?
“Required” BreakOut Box
• 2 types – Allow scanner connec>on or not – Indicate various parameters or not
What LED Is On and What does it Mean (AES WAVE Line Spi)
CAN Remains Ac>ve For Many Seconds
With This In Mind….
• Use the BOB or MP 1918 to show students that the system is awake
• Show how long system stays awake aber no inputs
• Emphasize to not disconnect anything with CAN awake
Single wire system
Dual wire CAN
MP-‐1918 CAN Bus
Mul>ple CAN may….
• Actually be available in DLC • Second set of high speed (+ and -‐) • Common module (Gateway) within 2 different CAN networks
• Power and/or ground supplied in usual manner
2012 GMC Terrain Low Speed 1 of 2
Low Speed 2 of 2
High Speed 1 of 2
High Speed 2 of 2
Enable Serial Data (LIN)
BCM Linear Interconnect (LIN)
Radio/HVAC Linear Connect
Chassis Expansion Module (2nd High Speed CAN)
Ford High Speed CAN Present
Medium CAN Present Pins 3 and 11 Module Communica>ons Network
Mul>ple CAN Systems
• Usually have one module common to both • This module may even be the gateway
– Responsible for communica>on – Wake up system
• In some cases – More than one module present in both CAN – Tough to figure what is gateway
Basic Diagnos>cs
• For a no communica>on or no start/crank • Pull barery • Ohm out high speed • Look for wake-‐up signal (DSO)
– May be either low speed or high speed
• Look for communica>on • Scan for available modules (module status)
• Disconnect the barery picture
The battery must be disconnected
Resistance Values • If circuit has
– two resistors in parallel • *Measured with the baDery
disconnected – Or “poof”
• Measuring the “bus” resistance
• Communica>on pathway – No pathway = – No communica>on
• Key is wiring diagram
Some Diagrams Might Not Show Resistors – Ohm meter tells story
Bat Disconnected. Pins 6 & 14 Ohmmeter Reading Ford Focus ‘08
Why Do an Ohmmeter Test??
• Basic info on opens and shorts • Does the system have the path for communica>on
• Communica>on wiring integrity • “might” be cause of no monitors • Aber DMM test, reconnect barery and scan • “Possibly” shut down monitor system • Switch to DSO and look for wake up
Wake Up Sig Low Speed
Low Speed CAN Bus Pin 1
CAN High (+) Pin 6
CAN Low (-‐) Pin 14
Pins 6 and 14
Mul>ple CAN may….
• Actually be available in DLC • Second set of high speed (+ and -‐) • Common module within 2 different CAN networks
• Power and/or ground supplied in usual manner
2012 GMC Terrain Low Speed 1 of 2
Low Speed 2 of 2
High Speed 1 of 2
High Speed 2 of 2
Enable Serial Data (LIN)
BCM Linear Interconnect (LIN)
Radio/HVAC Linear Connect
Chassis Expansion Module (2nd High Speed CAN)
DLC PinOut 2012 GMC Terrain
Pins 12 and 13 Chassis Expansion Module 2012 GMC Terrain
Pin 12 KOER 2012 GMC Terrain
Pins 12 & 13
Proof of High Speed CAN Mirror Image Pins 12 & 13
Pinging the Modules
• AutoEnginuity • Request module status • Part of start up
Or… Handheld Scanner and Simpler Vehicle
• Try to determine what you have prior to actually connec>ng
• Use the BOB and scanner in parallel
• Have the wiring diagram in front of you
• Hood DOWN • Pay aren>on to details
The Wake-‐up Call
• Hello, hello, • Communica>on taking place? – Is anyone listening – Is anyone talking
• Is anyone having problems (DTC’s)
• Pinging the modules
Module Status or “Hello Out There !!’
• Indicates that communica>on is occurring – Roll call
• 8 modules present – Same as wiring diagram?
• No DTC
2008 Pon>ac Sols>ce
Let’s Back Out of Single Wire CAN
• Select Dual Wire CAN • Enter • Look at wiring diagram • Will communica>on occur? • What modules might be on
the bus? • What DTC’s are present?
Complete Roll Call
• Indicates that communica>on is occurring
• 5 modules present – Same as wiring diagram?
• One has a DTC – Radio
Dual Wire CAN 2008 Sols>ce
Tes>ng Sequence Reviewed • With a no high speed communica>on vehicle
– Disconnect barery – Measure resistance between pins 6 and 14
• It must be correct !! • Fix it !
– Check for wake up signal (maybe low speed) – DSO KOEO or KOER
• Both high and low signal – Check for module communica>on
• If no – go to individual module B+ B-‐ and signal • Repair as needed or replace module – re-‐program?
– Check modules vs wiring diagram
Communica1on Enable and Linear Interconnect “CAN” Network (LIN) Not in DLC
STOP and look at a LIN • Linear interconnect network • Usually NOT in DLC • Usually a B+ or ground switch from a CAN module • Supplies power to other modules (some>mes addi>onal other than main power
• Sequence: – Gateway wake up signal – CAN comes alive – LIN turns on addi>onal components or modules – Everyone starts talking
Communica1on Enable and Linear Interconnect “CAN” Network (LIN) Not in DLC
Fair Winds
• Hope to see you at • NACAT 2015 in Joliet, IL • Or
– On the water • Thanks for arending • Don’t forget to thank our hosts for a great conference