Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT PRE-TENSIONER"
The Supplemental Restraint System such as "AIR BAG" and "SEAT BELT PRE-TENSIONER", used along with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted. Information necessary to service the system safely is included in the " SRS AIRBAG " and " SEAT BELTS " of this Service Information.
| WARNING | Always observe the following items for preventing accidental activation. To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death in the event of a collision that would result in air bag inflation, all maintenance must be performed by an authorized NISSAN/INFINITI dealer. Improper maintenance, including incorrect removal and installation of the SRS, can lead to personal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air Bag Module, see " SRS AIRBAG ". Never use electrical test equipment on any circuit related to the SRS unless instructed to in this Service Information. SRS wiring harnesses can be identified by yellow and/or orange harnesses or harness connectors. |
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
| WARNING | Always observe the following items for preventing accidental activation. When working near the Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the ignition ON or engine running, never use air or electric power tools or strike near the sensor(s) with a hammer. Heavy vibration could activate the sensor(s) and deploy the air bag(s), possibly causing serious injury. When using air or electric power tools or hammers, always switch the ignition OFF, disconnect the battery, and wait at least 3 minutes before performing any service. |
Scheme 4
Scheme 4: Service Notice or Precautions for EPS System
Scheme 5
- Check the following item when performing the trouble diagnosis. Check any possible causes by interviewing the symptom and it's condition from the customer if any malfunction, such as EPS warning lamp is turned ON, occurs. Check if air pressure and size of tires are proper, the specified part is used for the steering wheel, and control unit is genuine part. Check if the connection of steering column assembly and steering gear assembly is proper (there is not looseness of mounting bolts, damage of rods, boots or sealants, and leakage of grease, etc.). Check if the wheel alignment is adjusted properly. Check if there is any damage or modification to suspension or body resulting in increased weight or altered ground clearance. Check if installation conditions of each link and suspension are proper. Check if the battery voltage is proper. Check connection conditions of each connector are proper. Before connecting or disconnecting the EPS control unit harness connector, turn ignition switch "OFF" and disconnect battery ground cable. Because battery voltage is applied to EPS control unit even if ignition switch is turned "OFF". When connecting or disconnecting pin connectors into or from EPS control unit, take care not to damage pin terminals (bend or break). When connecting pin connectors, make sure that there are no bends or breaks on EPS control unit pin terminal.
- During quick steering, rasping noise may be heard from around the steering wheel. This is not a malfunction. The noise is an operating noise of the EPS system under normal conditions. If the rasping noise occurs during slow steering, this may not be an operating noise of the system. In this case, it is necessary to find out the location of the noise and repair, if necessary.
Scheme 6
Scheme 6: Component Parts Location
EPS Control Unit
- EPS control unit performs an arithmetical operation on data, such as steering wheel turning force (sensor signal) from the torque sensor, vehicle speed signal, etc. Then it generates an optimum assist torque signal to the EPS motor according to the driving condition.
- EPS control unit decreases the output signal to EPS motor while extremely using the power steering function (e.g., full steering) consecutively for protecting EPS motor and EPS control unit (Overload protection control).
- In SPORT mode, changes the steering assist characteristic to enhance a stable steering feel according to the mode signals from multi display unit via CAN communication. (Models with Integrated Control System)
EPS Motor
EPS motor provides the assist torque by the control signal from EPS control unit.
Reduction Gear
Reduction gear increases the assist torque provided from EPS motor with worm gears, and outputs to the column shaft.
Scheme 7
Scheme 7: EPS SYSTEM: System Description
- EPS control unit performs an arithmetical operation on data, such as steering wheel turning force (sensor signal) from the torque sensor, vehicle speed signal, etc. Then it generates an optimum assist torque signal to the EPS motor according to the driving condition.
- In case of an error in the electrical system, the fail-safe function stops output signals to the EPS motor. Refer to " «EPS SYSTEM: FAIL-SAFE»(ref-516435-S09970747522012120600000) ".
- EPS control unit decreases the output signal to EPS motor while extremely using the power steering function (e.g., full steering) consecutively for protecting EPS motor and EPS control unit (Overload protection control). Refer to " «EPS SYSTEM: PROTECTION FUNCTION»(ref-516435-S19350737762012120600000) ".
- Extensive steering at low speed will cause the EPS control unit and EPS motor to heat up, once temperature reaches critical point EPS control unit will reduce current to reduce heat up. System will recover as temperature lowers (reduced or no assistance).
- In SPORT mode, changes the steering assist characteristic to enhance a stable steering feel according to the mode signals from multi display unit via CAN communication. (Models with Integrated Control System)
Scheme 8
Multi display unit is applied to models with Integrated Control System.
INPUT/OUTPUT SIGNAL
Communicates the signal from each control unit via CAN communication.
| Control unit | Signal status |
|---|
| ECM | Transmits mainly the following signals to EPS control unit via CAN communication. Engine status signal |
| ABS actuator and electric unit (control unit) | Transmits mainly the following signals to EPS control unit via CAN communication. Vehicle speed signal |
| Combination meter | Transmits mainly the following signals to EPS control unit via CAN communication. Vehicle speed signal Receives mainly the following signals from EPS control unit via CAN communication. EPS warning lamp signal |
| Multi display unit (1) | Transmits mainly the following signals to EPS control unit via CAN communication. ECO mode signal NORMAL mode signal SPORT mode signal |
| (1) Models with Integrated Control System |
| (1) | Models with Integrated Control System |
EPS WARNING LAMP INDICATION
- Turn ON when there is a malfunction in EPS system. If indicates that fail-safe mode is engaged and enters a manual steering state (Control turning force steering wheel becomes heavy).
- Also turns ON when ignition switch is turned ON, for purpose of lamp check. Turns OFF after the engine starts, if system is normal.
| Condition | EPS warning lamp |
|---|
| Ignition switch ON. (Lamp check) | ON |
| Engine running. | OFF |
| EPS system malfunction [Other diagnostic item] | ON |
| CAUTION | EPS warning lamp also turns ON due to data reception error, CAN communication error etc. |
EPS SYSTEM: Fail-Safe
- If any malfunction occurs in the system, and control unit detects the malfunction, EPS warning lamp on combination meter turns ON to indicate system malfunction.
- When EPS warning lamp is ON, enters into a manual steering state. (Control turning force steering wheel becomes heavy.)
EPS SYSTEM: Protection Function
EPS control unit decreases the output signal to EPS motor while extremely using the power steering function (e.g., full steering) consecutively for protecting EPS motor and EPS control unit (Overload protection control). While activating overload protection control, the assist torque gradually decreases, and the steering wheel turning force becomes heavy. The normal assist torque is recovered if the steering wheel is not turned for a while.
FUNCTION
CONSULT can display each diagnostic item using the diagnostic test modes shown following.
| Diagnostic test mode | Function |
|---|
| ECU identification | The part number stored in the control unit can be read. |
| Self diagnostic result | Self-diagnostic results and freeze frame data can be read and erased quickly. (1) |
| Data monitor | Input/Output data in the EPS control unit can be read. |
| (1) The following diagnosis information is erased by erasing. |
| (1) | The following diagnosis information is erased by erasing. |
- DTC
- Freeze frame data (FFD)
SELF-DIAG RESULTS MODE
When "CRNT" is displayed on self-diagnosis result.
- The system is presently malfunctioning.
When "PAST" is displayed on self-diagnosis result.
- System malfunction in the past is detected, but the system is presently normal.
FREEZE FRAME DATA (FFD)
The following vehicle status is recorded when DTC is detected and is displayed on CONSULT.
| Item name | Display item |
|---|
| IGN COUNTER (0 - 39) | The number of times that ignition switch is turned ON after the DTC is detected is displayed. When "0" is displayed: It indicates that the system is presently malfunctioning. When except "0" is displayed: It indicates that system malfunction in the past is detected, but the system is presently normal. NOTE: Each time when ignition switch is turned OFF to ON, numerical number increases in 1-->2-->3...38-->39. When the operation number of times exceeds 39, the number do not increase and "39" is displayed until self-diagnosis is erased. |
| NOTE |
|---|
| Each time when ignition switch is turned OFF to ON, numerical number increases in 1-->2-->3...38-->39. When the operation number of times exceeds 39, the number do not increase and "39" is displayed until self-diagnosis is erased. |
DATA MONITOR MODE
| Monitor item (Unit) | Remarks |
|---|
| BATTERY VOLT (V) | Displays the power supply voltage for EPS control unit. |
| TORQUE SENSOR (Nm) | Displays steering wheel turning force detected by torque sensor. |
| MOTOR CURRENT (A) | Displays the current value consumed by EPS motor. (1) |
| MOTOR SIG (A) | Displays the current commanded value to EPS motor. |
| ASSIST TORQUE (Nm) | Displays assist torque of EPS motor being output by the electric power steering. |
| C/U TEMP (°C) or (°F) | Displays the temperature of the EPS control unit. |
| ASSIST LEVEL (%) | Normally displays 100%. In case of an excessive stationary steering, the assist curvature gradually falls. However, it return to 100% when left standing. (2) |
| VEHICLE SPEED (km/h) or (MPH) | Vehicle speed is displayed from vehicle speed signal via CAN communication. (3) |
| WARNING LAMP (On/Off) | EPS warning lamp control status is displayed. |
| ENGINE STATUS (Stop/Run) | Engine speed is displayed from engine status signal via CAN communication. |
| STEERING MODE (NORMAL/SPORT) (4) | Display the driving mode of Integrated Control System received through CAN communication. |
| (1) Almost in accordance with the value of "MOTOR SIG". It is not a malfunction though these values are not accorded when steering quickly. (2) Normally displays 100%. In case of an excessive stationary steering, the assist curvature gradually falls. However, it returns to 100% when left standing. (3) It is not a malfunction, though it might not be corresponding just after ignition switch in turned ON. (4) Displays NORMAL in models without Integrated Control System. |
| (1) | Almost in accordance with the value of "MOTOR SIG". It is not a malfunction though these values are not accorded when steering quickly. |
| (2) | Normally displays 100%. In case of an excessive stationary steering, the assist curvature gradually falls. However, it returns to 100% when left standing. |
| (3) | It is not a malfunction, though it might not be corresponding just after ignition switch in turned ON. |
| (4) | Displays NORMAL in models without Integrated Control System. |
PHYSICAL VALUES
| Terminal No. (Wire Color) | Description | Condition | Value (Approx.) |
|---|
| + | | Signal name | Input/Output |
| 1 (P) | | CAN-L | Input/Output | | |
| 2 (L) | | CAN-H | Input/Output | | |
| 4 (LG) | Ground | Ignition power supply | Input | Ignition switch: ON | 9 - 18.2 V |
| Ignition switch: OFF | 0 V |
| 9 (R) | Ground | Battery power supply | Input | Always | 9 - 18.2 V |
| 10 (B) | Ground | Ground | | Always | 0 V |
Fail-Safe
- If any malfunction occurs in the system, and control unit detects the malfunction, EPS warning lamp on combination meter turns ON to indicate system malfunction.
- When EPS warning lamp is ON, enters into a manual steering state. (Control turning force steering wheel becomes heavy.)
Protection Function
EPS control unit decreases the output signal to EPS motor while extremely using the power steering function (e.g., full steering) consecutively for protecting EPS motor and EPS control unit (Overload protection control). While activating overload protection control, the assist torque gradually decreases, and the steering wheel turning force becomes heavy. The normal assist torque is recovered if the steering wheel is not turned for a while.
DETAILED FLOW
- INTERVIEW FROM THE CUSTOMER Clarify customer complaints before inspection. First of all, perform an interview utilizing " «DIAGNOSTIC WORK SHEET»(ref-516435-S32399777362012120600000) " and reproduce symptoms as well as fully understand it. Ask customer about his/her complaints carefully. Check symptoms by driving vehicle with customer, if necessary. CAUTION: Customers are not professional. Never guess easily like "maybe the customer means that...," or "maybe the customer mentions this symptom". GO TO 2.
- CHECK SYMPTOM Reproduce the symptom that is indicated by the customer, based on the information from the customer obtained by interview. Also check that the symptom is not caused by protection function. Refer to " «PROTECTION FUNCTION»(ref-516435-S00260790892012120600000) ". CAUTION: When the symptom is caused by normal operation, fully inspect each portion and obtain the understanding of customer that the symptom is not caused by a malfunction. GO TO 3.
- PERFORM SELF-DIAGNOSIS With CONSULT Perform self-diagnosis. Is any DTC detected? YES: Record or print DTC and freeze frame data (FFD). GO TO 4. NO: GO TO 6 .
- RECHECK SYMPTOM With CONSULT Erase self-diagnostic results for "EPS". Perform DTC confirmation procedures for the error detected system. NOTE: If some DTCs are detected at the same time, determine the order for performing the diagnosis based on " «DTC INSPECTION PRIORITY CHART»(ref-516435-S24352678592012120600000) ". Is any DTC detected? YES: GO TO 5. NO: Check harness and connectors based on the information obtained by interview. Refer to " «INTERMITTENT INCIDENT»(ref-516389-S36169925192012120600000) ".
- REPAIR OR REPLACE ERROR-DETECTED PARTS Repair or replace error-detected parts. Reconnect part or connector after repairing or replacing. When DTC is detected, erase self-diagnostic results for "EPS". GO TO 7 .
- IDENTIFY ERROR-DETECTED SYSTEM BY SYMPTOM DIAGNOSIS Estimate error-detected system based on symptom diagnosis and perform inspection. Can the error-detected system be identified? YES: GO TO 7. NO: Check harness and connectors based on the information obtained by interview. Refer to " «INTERMITTENT INCIDENT»(ref-516389-S36169925192012120600000) ".
- FINAL CHECK With CONSULT Check the reference value for EPS control unit. Recheck the symptom and check that symptom is not reproduced on the same conditions. Is the symptom reproduced? YES: GO TO 3. NO: INSPECTION END
Component Function Check
- CHECK THE ILLUMINATION OF THE EPS WARNING LAMP Check that the EPS warning lamp turns ON when ignition switch turns ON. Then, EPS warning lamp turns OFF after the engine is started. Is the inspection result normal? YES: INSPECTION END NO: Perform trouble diagnosis. Refer to " «DIAGNOSIS PROCEDURE»(ref-516435-S11593352282012120600000) ".
