2004 Nissan Pathfinder 3.5 SE Inoperative Accelerator Pedal/Throttle Body DTC P1122 & P1126 - MechoMedics

Friday, 1 June 2018

2004 Nissan Pathfinder 3.5 SE Inoperative Accelerator Pedal/Throttle Body DTC P1122 & P1126

2004 NISSAN PATHFINDER V6 3.5 SE UNDERHOOD VIEW

Hello Readers, this will be brief but prove useful to other Technicians and Mechanics; a Mechanic friend actually dragged me into this fix and it was fast and with a permanent fix done.


DTCs
1. P1490: VC/V BYPASS/V
2. P1122: ETC FUNCTION/CIRC.
3. P0031: HO2S1 HTR (B1)
4. P1126: ETC MOT PWR
DTC Snapshot 

The 2004 Nissan 3.5 SE V6 is electrically intelligent with it's Throttle designed as  an Electronic Throttle Control Actuator (Drive-By-Wire-Throttle). The throttle is powered by electrical voltage and signal sent from the Engine Control Module (ECM), this is based on the calculated value of Throttle Valve angle opening gotten from the Accelerator Pedal Position (APP) Sensor (located on Acceletator Pedal driver's side) depression by the Driver. The Electronic Throttle Control Actuator comprises of Sensors (Throttle Position Sensor (TPS) 1, and  Throttle Position Sensor (TPS) 2), Accelerator Pedal Position (APP) Sensor 1, Accelerator Pedal Position (APP) Sensor 2, Throttle Actuator, Throttle Valve and Throttle Control Motor. And it serves in opening up and closing the manifold for Idle air intake and also air intake for various level of acceleration i.e. Wide Open Throttle (WOP), deceleration and varing speed of take-off. 
Electronic Throttle Control Actuator System WD.

The wiring system of the Electronic Throttle Control Actuator System is protected by a 15A fuse (Fuse 70 of Fuse and Fusible Link Box in Engine Relay Box 2). [ETC WD image drafted by MechoMedics and prepared from Mitchell OnDemand 1]
Underhood Relay Box 2 Cover and Fuse & Relay location.

This Fuse prevent a surge of voltage from damaging the Throttle Control Motor Relay (located in Engine Relay Box 2) ECM and it's internal Electronic Throttle Control Actuator drivers. The fuse is wired as HOT AT ALL TIMES and connected to the Throttle Control Motor Relay which in it's closed position allows Battery Voltage to reach the ECM as it receive a varying ground control whose voltage varies based on the Accelerator Pedal Position (APP) depression by the driver.

The observable symptom with the Fuse broken is that the Engine will not Rev above 2000RPM on the Tachometer (even at fully depressed Accelerator Pedal) and this was experienced by my friend. 
Maximum RPM below 2000 at fully depressed Accelerator Pedal

Fully depressed Accelerator Pedal

By a detailed inspection and diagnosis of the fault  DTCs P1122 and P1126 were related to the fault and further pin point testing located the blown fuse. Replacement of the blown 15A fuse fixed this fault.  Pictures added to guide you if you have a similar fault and I hope you find this information useful. Cheers!



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