U0001
COMPONENT LOCATION
GENERAL DESCRIPTION
Several control units are applied to electronically controlled vehicles. These units perform each control with informations from various sensors. Thus, sharing signal information from sensors is needed, so CAN communication type whose communication speed is high and insensitive to electrical noise by spark generation is adopted to controlling power-train(PCM, ABS, ESP)
As sharing signals of engine speed, APS, gear shifting, torque reduction in ESP,ABS and various modules, active control is performed.
GENERAL DESCRIPTION
The TCM can either receive data from the Engine Control Module or ABS control module, or it can send data to the ECM and ABSCM by using CAN communication. The CAN communicaton is one of the vehicle communication methods, which is now widely used to transfer the vehicle data.
DTC DESCRIPTION
Checking CAN communication, under detecting condition, if an error within the detecting condition is detected for more than 1.5 sec., PCM sets U0001. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
DTC Description
When the TCM cannot read the data from the ECM through the CAN-BUS line, the TCM sets this code.
CAN-BUS circuit malfunctioning or ECM can be a possible cause of this DTC.
DTC DETECTING CONDITION
DTC DETECTING CONDITION
SIGNAL WAVEFORM AND DATA
SPECIFICATION
SCHEMATIC DIAGRAM
MONITOR DTC STATUS
1. Check DTC Status
(1) Connect scantool to Data Link Connector(DLC).
(2) IG "ON".
(3) Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F4(DTAL) to check DTC's information from the DTCs menu
(4) Read "DTC Status" parameter.
(5) Is parameter displayed "Present fault"?
YES
> Go to "Terminal and connector inspection" procedure.
NO
> Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES
> Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
> Go to "Signal Circuit Inspection" procedure.
SIGNAL CIRCUIT INSPECTION
1. Check CAN BUS resistance in Data Link Connector
(1) Ignition "OFF"
(2) Measure the resistance between terminals 3 and 11 of data link connector (Test 1)
(3) Disconnect PCM connector.
(4) Measure the resistance between terminals 3 and 11 of data link connector (Test 2)
Specification : PCM and ABS(or ESP) connected : 60 ± 3Ohms (Test 1)
PCM and ABS(or ESP) disconnected : 120 ± 3Ohms (Test 2)
(5) Is CAN BUS resistance within the specification?
YES
> Go to "2.Check short to ground in CAN BUS" as follows.
NO
> Below 10Ohms for both conditions(disconnected, connected) : Repair short between CAN BUS lines and go to "Verification of Vehicle Repair".
> 120Ohms for both conditions(disconnected, connected) : Go to "4. Check CAN BUS continuity".
> Infinite Ohms for both conditions(disconnected, connected) :Repair open in CAN communication circuit between DLC terminal and In-pannel junction box.
2. Check short to ground in CAN BUS
(1) Ignition "OFF"
(2) Disconnect PCM and ABS(or ESP) connector.
(3) Check continuity between DLC terminal 3 and chassis ground. (CAN HIGH line)
(4) Check continuity between DLC terminal 11 and chassis ground. (CAN LOW line)
Specification : Discontinuity ( Infinite Ohms )
(5) Is measured resistance within the specification?
YES
> Go to "3. Check short to battery in CAN BUS".
NO
> Repair short to ground in circuit and go to "Verification of Vehicle Repair".
3. Check short to battery in CAN BUS
(1) Ignition "OFF"
(2) Disconnect PCM and ABS(or ESP) connector.
(3) Ignition "ON"
(4) Measure the voltage of DLC terminal 3. (CAN HIGH line)
(5) Measure the voltage of DLC terminal 11. (CAN LOW line)
Specification : 0.0V~0.1V
(6) Is measured resistance within the specification with both connector disconnected?
YES
> Go to"4. Check CAN BUS continuity" as follows.
NO
> Repair short to battery and go to "Verification of Vehicle Repair".
4. Check CAN BUS continuity
(1) Ignition "OFF"
(2) Disconnect PCM and ABS(or ESP) connector.
(3) Check continuity in CAN HIGH line.
( CAN HIGH : PCM connector (C201-1) terminal 41, ABS connector terminal 11, ESP connector terminal 7, Data link connector(DLC) terminal 3 )
(4) Check continuity CAN LOW line.
( CAN LOW : PCM connector (C201-1) terminal 42, ABS connector terminal 10, ESP connector terminal 22, Data link connector(DLC) terminal 11 )
Specification : Continuity(below 1.0Ohms )
(5) Is the measured resistance within the specification?
YES
> Go to "Component Inspection".
NO
> Repair open in CAN BUS line and go to "Verification of Vehicle Repair".
COMPONENT INSPECTION
1. Check CAN communication waveform generation
(1) Ignition "OFF"
(2) Connect 2 channel scope to DLC terminal 3(CAN HIGH) and 11(CAN LOW).
(3) Ignition "ON" after connecting only PCM to CAN BUS.
(4) Ignition "ON" after connecting only ABS or ESP module to CAN BUS.
Specification : At Ignition "ON", the waveform same as "Signal Waveform & Data" of above signal waveform.
** Different from "Signal Waveform & Data", if 1) both CAN HIGH and LOW signal are fixed at 2.5 V or
2) HIGH and LOW signal are fixed at 3.5 V and 1.5 V, respectively, it is due to communication error between modules.
(5) Does correct waveform generate from each module?
YES
> Go to "Verification of Vehicle Repair".
NO
> Replace the module which generates poor communication waveform, and go to "Verification of Vehicle Repair".
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions
4. Monitor that all rediness test have been verified as " Complete "
5. Are any DTCs present ?
YES
> Go to the applicable troubleshoooting procedure.
NO
> System is performing to specification at this time.