In this issue of Keep Those Trannys Rolling, we are going to take a look at Nissan’s CVT-Driven All-Wheel Drive System. In 2013, Nissan introduced the 2013 Pathfinder, equipped with a 3.5L engine, a RE0F10E CVT transmission, a full-time transfer case, and an electronically controlled coupling rear differential. This was a complete change from earlier models, which were equipped with a 4.0L or a 5.6L engine, a RE5R01A transmission, and an electronically controlled transfer case. With the introduction of the RE0F10E CVT transmission in the 2013 Pathfinder, it became necessary to redesign the All-Wheel Drive (AWD) system. This newly designed AWD system would allow the Pathfinder to become more fuel-efficient and provide a more seamless AWD experience than prior-year models. Now, let’s take a look at Nissan’s CVT-driven AWD system.
Nissan’s CVT Driven AWD System:
This AWD system was designed in 2013 and used in the Pathfinder from 2013 to 2020. In 2022, Nissan updated the AWD system again to allow for a more seamless AWD operation. Nissan’s CVT-driven AWD system consists of a:
- CVT transmission
- Full-time transfer case,
- Electronically controlled differential,
- 4WD control unit/module
- 4WD mode switch
- Indicator light, necessary wiring, and connections to operate the AWD system
Now let’s take a look at each of these components.
Constantly Variable Transmission (CVT):
The RE0F10E CVT transmission was introduced into the Pathfinder line in 2013 and continued to 2015, when the RE0F10J CVT transmission replaced it. The use of the RE0F10J CVT transmission continued until late 2020. The Pathfinder line disappeared in 2021 and was brought back in 2022 with a GE9F10A (9-speed) automatic transmission.
Full-Time Transfer Case:
The purpose of the transfer case is to transfer power from the transmission to the Electronically Controlled Differential. The 2013-2020 Pathfinder uses a full-time transfer case. The transfer case assembly consists of:
- Transfer Case
- Transfer Cover
- Drive Pinion
- Ring Gear Shaft
- Companion Flange
- Bearings and Seals
The transfer case assembly does not require servicing. If the transfer case is replaced or repaired, it requires ½ pint of Genuine Nissan Differential Oil Hypoid Super GL-5 80W-90W or equivalent to fill the transfer case assembly.
Electronically Controlled Differential:
The purpose of the Electronically Controlled Differential is to distribute power/torque to the rear wheels as needed during AWD operation. The Electronically Controlled Differential consists of a/an:
- Electronically Controlled Coupler (Figure 1), which contains a main clutch, a control clutch, an actuating cam, a solenoid, and an electromagnet.
- Differential assembly
The Electronically Controlled Differential uses 1 pint of Genuine Nissan Differential Oil Hypoid Super Semisynthetic API GL-5 SAE 75W-90W or equivalent to fill the differential. The Electronically Controlled Coupler is a sealed assembly with its own lubrication. The uid in the coupler is not serviceable.
4WD Control Unit:
The purpose of the 4WD control unit/module is to control the AWD system. The 4WD control unit/module uses inputs from the Engine Control Module (ECM), Anti-lock Brake Control Module (ABS), and Body Control Module (BCM) to control the AWD system.
4WD Control Switch:
The purpose of the 4WD switch is to notify the 4WD control unit of a requested AWD operation. The 4WD switch controls the 2WD, 4WD, and Auto modes of the AWD system. 4WD Indicator Light: The purpose of the 4WD indicator light is to notify the driver of any AWD concerns.
Basic AWD System Operation:
The AWD system uses inputs from the 4WD Switch to determine basic AWD operation. The AWD system offers 2WD, 4WD, and Auto AWD modes. Now, let’s take a look at how the AWD system operates in each of these modes.
- 2WD Mode: In 2WD mode, the 4WD control unit disables the electronic coupler in the rear differential, allowing the front wheels to drive the vehicle.
- 4WD Mode: In 4WD mode, the 4WD control unit fully engages the electronic coupler in the rear differential, thereby allowing the front and rear wheels to drive the vehicle.
- AWD Mode: In AWD Mode, the 4WD control unit varies the electronic coupler engagement in the rear differential to control the AWD system as needed.
How does the AWD System Work:
Nissan’s AWD system is controlled by the 4WD control unit/module. The 4WD control unit/module monitors inputs from the Engine Control Module (ECM), the Anti-lock Brake Control Module (ABS), the Body Control Module (BCM) via the data line system, and the 4WD switch. In AWD mode, the 4WD control unit monitors the ABS wheel speeds and engine load. If the 4WD control unit detects excessive wheel slip from the ABS control module or excessive engine load from the ECM, the 4WD control unit/module will pulse the electronic coupler (in the rear differential) on and off to control wheel slip. Now that we have a better understanding of how the AWD system works, we’re going to take a look at the diagnostic routines used to keep this AWD system working properly.
Diagnosing Nissan’s CVT-Driven AWD System:
Diagnosing Nissan’s CVT-Driven AWD System is straightforward. A ‘4WD Error: See Owner’s Manual’ message will display in the instrument cluster indicating a problem has occurred (Figure 2). The rst step in diagnosing Nissan’s CVT-driven AWD system is to monitor the 4WD indicator lamp. The 4WD warning indicator is illuminated or flashing when there is a malfunction in the 4WD system. An illuminated or ashing 4WD warning indicator lamp indicates that the vehicle’s AWD system is in fail-safe mode and has shifted to front-wheel drive. The 4WD warning light is capable of indicating basic problems by illuminating or flashing. Let’s take a look at how the 4WD warning light works.
4WD Warning Light Operation:
- 4WD warning light illuminated indicates AWD malfunction, check for codes in the 4WD control unit/module
- The 4WD warning light flashes rapidly, indicating the protection function is activated due to a heavy load on the electronically controlled coupling. (The 4WD system is not malfunctioning, and the 4WD system changes to front wheel drive.)
- The 4WD warning light flashes slowly, indicating a significant difference in the diameter of the front/rear tires.
- 4WD warning light off indicates the AWD system is operating normally
Checking for Codes:
When diagnosing AWD system concerns, it is recommended to check the vehicle’s individual control modules for codes. If codes are present, document and clear all codes in all modules. After the codes have been documented and cleared, it is recommended to test-drive the vehicle to duplicate any AWD concerns. If you encounter an AWD concern during the test drive and the 4WD warning light is illuminated or flashing, it would be recommended to check the 4WD control unit for codes. The following is a list of codes you may find in the 4WD control unit/module.
- C1201 – Controller Failure
- C1203 – ABS System
- C1204 – 4WD Solenoid
- C1205 – 4WD Actuator Relay
- C1209 – Mode Switch
- C1210 – Engine Signal #1
- P1804 – Control Unit #3
- P181F – Incomplete Calibration
- U1000 – Can Comm Circuit
- U1010 – Control Unit (CAN)
Diagnosing 4WD Control Unit/Module Codes:
When diagnosing 4WD control unit/module codes, you should always start by checking the battery condition and connections. Low or erratic system voltage can and will interfere with AWD system operation. After verifying the battery condition and that the connections are good, you can start your diagnostic routines for codes set in the 4WD control unit/module.
- C1201- Controller Failure: 4WD Control Unit/Module has encountered an internal failure. *Check 4WD Control Unit/Module power and grounds. If code returns, replace 4WD Control Unit/Module.
- C1203- ABS System: 4WD Control Unit/Module has received a message from the ABS Control Module indicating a possible wheel speed sensor concern. *Check ABS for codes and repair as needed.
- C1204- 4WD Solenoid: 4WD Control Unit/module detects a problem in the 4WD solenoid circuit. *Check wiring and connections related to the 4WD solenoid circuit. Check 4WD solenoid resistance; it should be 2.45 ohms. Check for possible internal malfunction in electronic coupler assembly (not serviceable). *Check the possible 4WD control Unit/Module.
- C1205- 4WD Actuator Relay: 4WD Control Unit/Module detects a problem in the 4WD Actuator relay circuit (located in the 4WD Control Unit/ Module). *Check 4WD Control Unit/ Module power and ground circuits. Check for possible internal malfunction in the electronic coupler assembly.
- C1209- Mode Switch: 4WD Control Unit/Module detects more than two switch inputs from the Mode Switch. *Check Mode Switch wiring and connections. Check the Mode Switch operation. Check the possible 4WD Control Unit/Module.
- C1210-Engine Signal #1: 4WD Control Unit/Module has received a message from the ECM indicating an engine performance concern exists. *Check ECM for codes and repair as needed.
- P1804-Control Unit #3: 4WD Control Unit/Module detects a malfunction in the memory (EEPROM) of the 4WD Control Unit/Module. *Check 4WD Control Unit/Module power and grounds. If code returns, replace 4WD Control Unit/Module.
- P181F- Incomplete Calibration: 4WD Control Unit/Module has received incomplete calibration information from the final drive unit. *Check final drive unit (electronic coupler) calibration number in 4WD Control Unit/Module.
- U1000- Can Comm Circuit- 4WD Control Unit/Module is not transmitting or receiving CAN communication for more than 2 seconds. *Check CAN communication lines. Check 4WD Control Unit/Module power and grounds. Check the possible 4WD Control Unit/Module.
- U1010- Control Unit CAN: 4WD Control Unit/Module detects an internal CAN control problem. *Check 4WD Control Unit/Module powers and grounds. If the code returns, replace the 4WD control Unit/Module.
Voltage checks can be performed by back-probing the control module connector and using a digital volt-ohm meter or DSO oscilloscope (Figure 3). It is recommended to refer to your specific vehicle’s wiring schematics for circuit information.
The Electronic coupler can be disabled by removing fuse #62(10a) from the fuse/link relay box (Figure 4) located on the left side of the engine compartment.
With a better understanding of Nissan’s CVT-driven AWD system, you should have no problem keeping your 2013-2020 AWD Nissan Pathfinder rolling down the road!
