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. Information necessary to service the system safely is included in the SRS AIRBAG and SEAT BELTS article of this Service Information.
| WARNING | To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death in the event of a collision which 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 the SRS AIRBAG . Do not 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 | When working near the Airbag Diagnosis Sensor Unit or other Airbag System sensors with the Ignition ON or engine running, DO NOT 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 three minutes before performing any service. |
Service Notice and Precautions for EPS System
- Check the following item when performing the trouble diagnosis: Check for possible causes of the malfunction by interviewing the customer as to what conditions were present when the symptom occurred. Check if the steering wheel and the EPS control unit are genuine parts. Check if the air pressure and size of each tire is correct. Check if the installation of the links and suspension components are correct. Check if the tires are worn evenly, indicating the wheel alignment is correct. Check if the installation of the steering column and the steering gear are correct. Check for loose bolts, damaged links, cracked boots and leaking grease, etc. Check for damage or modification to suspension or body resulting in increased weight or altered ground clearance. Check if the battery voltage is proper. Check the EPS control unit harness to be sure the harness connectors are fully seated.
- Before connecting or disconnecting the EPS control unit harness connector, turn ignition switch "OFF" and disconnect the battery cable from the negative terminal. Battery voltage is applied to the EPS control unit even if ignition switch is turned "OFF".
Scheme 9
Scheme 9: Component Parts Location
| No. | Component | Function |
|---|
| 1. | Combination meter (EPS warning lamp) | Transmits mainly the following signal to EPS control unit via CAN communication. Vehicle speed signal (Meter) Turns ON the EPS warning lamp according to the signal from EPS control unit via CAN communication. For detailed installation location, refer to " METER SYSTEM: COMPONENT PARTS LOCATION ". |
| 2. | ABS actuator and electric unit (control unit) | Transmits mainly the following signal to EPS control unit via CAN communication. Vehicle speed signal (ABS) For detailed installation location, refer to " COMPONENT PARTS LOCATION ". |
| 3. | ECM | Transmits mainly the following signals to EPS control unit via CAN communication. Engine status signal For detailed installation location, refer to " ENGINE CONTROL SYSTEM: COMPONENT PARTS LOCATION ". |
| Receives mainly the following signal from EPS control unit via CAN communication. EPS torque signal |
| 4. | EPS motor | Refer to " EPS MOTOR, TORQUE SENSOR, REDUCTION GEAR ". |
| 5. | Reduction gear | Refer to " EPS MOTOR, TORQUE SENSOR, REDUCTION GEAR ". |
| 6. | EPS control unit | Refer to " EPS CONTROL UNIT ". |
| 7. | Torque sensor | Refer to " EPS MOTOR, TORQUE SENSOR, REDUCTION GEAR ". |
Scheme 10
Scheme 10: EPS Control Unit
- EPS control unit (1) is installed to steering column assembly.
- 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).
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.
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. DTC Freeze frame data (FFD) |
| (1) | The following diagnosis information is erased by erasing. |
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.
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 does 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. |
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 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. |
| (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, through it might not be corresponding just after ignition switch in turned ON. |
| (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, through it might not be corresponding just after ignition switch in turned ON. |
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 (Y) | Ground | Ignition power supply | Input | Ignition switch: ON | Battery voltage |
| Ignition switch: OFF | 0 V |
| 13 (R) | Ground | Torque sensor power supply | Output | Ignition switch: ON | 5 V |
| Ignition switch: OFF | 0 V |
| 14 (Y) | Ground | Torque sensor sub | Input | Ignition switch: ON | Steering wheel: Not steering (There is no steering force) | 2.5 V |
| Engine running | Steering wheel: steering | 1.6 V - 3.4 V (The value is changed according to steering left or right) |
| 15 (B) | Ground | Torque sensor ground | Input | Always | 0 V |
| 16 (W) | Ground | Torque sensor main | Input | Ignition switch: ON | Steering wheel: Not steering (There is no steering force) | 2.5 V |
| Engine running | Steering wheel: steering | 1.6 V - 3.4 V (The value is changed according to steering left or right) |
| 17 (R) | Ground | Battery power supply | Input | Always | Battery voltage |
| 18 (B) | Ground | Ground | | Always | 0 V |
| 19 (-) | | Motor + | | | |
| 20 (B) | | Motor | | | |
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, the system enters into a manual steering state. (Steering wheel turning force becomes heavy.)
- Under abnormal vehicle speed signal conditions, vehicle speed is judged as constant.
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 reactivates by no steering.
DETAILED FLOW
- INTERVIEW FROM THE CUSTOMER Clarify customer complaints before inspection. First of all, perform an interview utilizing " «DIAGNOSTIC WORK SHEET»(ref-675617-S08883358872014120500000) " and reproduce symptoms to understand them fully. Ask customer about his/her complaints carefully. Check symptoms by driving vehicle with customer, if necessary. CAUTION: Customers are not professional. Never make assumptions like "maybe the customer means that...," or "maybe the customer mentioned 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-675617-S15972440672014120500000) ". 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 for "EPS". Is any DTC detected? YES: Record or print self-diagnosis results. GO TO 4. NO: GO TO 6 .
- RECHECK SYMPTOM With CONSULT Erase self-diagnostic results for "EPS". Perform DTC confirmation procedures for the malfunctioning 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-675617-S24630652042014120500000) ". 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-675571-S38824794042014120500000) ".
- REPAIR OR REPLACE MALFUNCTIONING COMPONENT Repair or replace malfunctioning component. Reconnect part or connector after repairing or replacing. When DTC is detected, erase self-diagnostic results for "EPS". : GO TO 7 .
- IDENTIFY MALFUNCTIONING SYSTEM BY SYMPTOM DIAGNOSIS Identify malfunctioning system based on symptom diagnosis and perform inspection. Can the malfunctioning system be identified? YES: GO TO 7. NO: Check harness and connectors based on the information obtained by interview. Refer to " «INTERMITTENT INCIDENT»(ref-675571-S38824794042014120500000) ".
- 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-675617-S24255199812014120500000) ".
