Hi we have encountered same error code 514.530
Upon checking we notice ps.c not activate.
We have change out the 2 igbt still the same problem.
Does ps.c need to be energized first or isit because of the fault that cause it not to activate.

For the benefit of others- Nissan P02 had power steering fault-codes 514 and 526. Tested IGBTs -one bad, replaced both upgrading from75A to 100A. Also changed current sensor because it showed.2 ohms instead of the.01 ohms stamped on it. New one had same resistance of.2- opened old and it is simply a corrugated resistance strip encased in cement- very simple- if continuity then probably good. New IGBTs didn't remedy. Sent board to uniparts, they found issues and warned to check IGBTs before install, as bad transistors will again blow the repaired board (the former go first then the board). Now functioning. Fault was probably caused by an obstructed steering wheel. Keep battery volts up (thus current normal)and set steering assist current level to 85% instead of 110% (press FN! and 3 at key-on, scroll down to PS). Uniparts said they do these repairs continuously.

Has same issue with the steering. replaced motor first then four sets of ibgs in till it worked. Ran good for a week. then burnt out motor. replaced motor and now have very little steering assist. removed tested and regreased motor drive unit. checked steering box and tried spare card. ran new wires to motor and even another set of igbs from dealer and changed current sensor. I seem to be only getting 8vdc to motor. an amp probe on lock shows 24 amps. unlocked i see 1 amp.I just got in a 3000 with similer steering and so far i know the card is good. will be testing the rest later next week.

Thanks for sharing this information.

I got my card back today from Nissan,they said it did have a issue and they fixed it, how ever ,,,,,, I'm having the exact same issues ,it is steering only one direction and it is still not accelerating properly,u had mentioned a steering sensor on the colum and also checking the foot switch pot,could u go into more depth, Im just about at the end of rope lol,any advise or thoughts would be great

If you know how to check sensors and such through the meter panel, i would start. Verifying proper accelerator pot voltages and smoothness of the voltage ramp while slowly operating accelerator will sure shorten the diagnostic time on this. Then again it could have been a card issue all alone.

thanks for the reply and info, i can reverse the steering wires on the motor and get it 2 steer the other way,i dont know what that means,also i sent my card and transistors off to nissan to be checked,let me rephrase the acceleration issue,its not really jumping its like its going into the higher tram u have to push the accelorator almost all the way down to get it 2 move, does that tell u anything
thanks tony

If you now have steering to one side and not the other then it is possible you have a mechanical binding in linkages or bent power steer cylinder screw. Also the steer sensor that is mounted to the steer sector could be flaking out and or damaged card.

As far as the jumping on acceleration could be due to setting of acceleration rate, drive motor brushes, accelerator pot and or damaged card.

We just installed new igbts set, we didn't have any ps now we have it steering to left only, also the machine isn't running smoothly it started jumping when u accelerate any advice would be appreciated

Hello, I came across this discussion,I have a Nissan electric lift that is giving me ps problems it will steer one way but not the other,has anyone ever came across this problem any input greatly appreciated

Also, remember to run a complete diagnostic check after installing new idgets,and replacing or unplugging panel, prior to attempt steering of unit, learned this the hard way, above advice is very good, also has been awhile since I worked on one, but them little wires were famous for coming unplugged.

As RCAV8TOR suggested I would start with verifying the correct operation and calibration of the steering sensor and the mechanical parts that operate it (located in bottom of column below floorboards).

Mike this is where i am thinking the problem originally started with steering. Verify that you have the igbt's properly wired. If you know how to get into diagnostics screen then go to steering sensor. What you want to look for is neutral, left and right parameters. See if the sensor is with in these parameters. If not then ahjust the sensor or you have a bad sensor or lever in the steer sector. Next inspect the linear actuator/ power steer cylinder to see if it is bent. You will need to remove the clamp from the rubber boot at the tail shaft and slideback toward the front of unit. With unit jacked and blocked up. turn the steering until the rod is fully extended. It will be a screw drive. if it is bent, it will bind. While up in the air also check the king pin thrust bearings as well. Check back with what you find.

Ok steering has been restored however a new problem has come up. there isnt any electrical problems according to the self checking but steering is very hard in only one direction. The forklift can turn left very easily but turning right the wheel becomes very stiff and hard to turn.

Also this is after we changed out the IGBT transistors and repaired the board. the wires have all been plugged in the right order now and all electrical problems seem to be out of the way.

Small control wires on igbt's should be installed as follows:

(green&yellow) (blue&red) (pink&white) (black&orange)

First off is the print card damaged? If all the wires are not connected, you will get an error code as the unit on power up runs a self test. Have you tried to plug in the 2 wires back into the igbt(s)? The color coding on the wires have a rhyme and resoning. From left to right and starting on the left steering IGBT, they will be in paired alphabetical order when connected( first letter of wire color). for example....... Blue Red, Pink White, Green Yellow, Black Orange if i remember right. I dont dont have a service manual with be but i think you see what i am saying. If the truck has not been tampered by anyone when it went down then the simple reconnect should correct the issue. If not then it could be safe to say that it is possible the connectors that were unplugged were not installed properly on the gate pins and have possibly arched and overheated the gates. This could cause a short in the transistors. But usually when a short is on the gate side, it blows the print card. Let me know the order the wires were plugged in.

Thanks RCAV8TOR much appreciated for your help. I do have limited experience in electrical repair I did what you said and there were no melted wires or over heating. However of the 8 wires coming out of the steering transistors some of them only had 1 of the pair plugged in. So only 6 connections were plugged in instead of the 8. Could this have been the cause of the problem and damaging the print board? Also some additional info I was notified of after
- The previous person that tried fixing this had made the owners of the forklift purchase a new board already and the forklift worked fine for about 10 mins once the new board was in. But after that the same problem came back up. So my guess is that those 8 connections that were supposed to be all connected caused damage to the new board?

I am assuming you have knowledge in electric forklift repair. If you have zero experience with one of these, i highly suggest to call your local Unicarrier dealer. If feeling a little spunky, then i would first off make use of a camera and take pics of what you are about to disaasemble. Locate a static strap ( If needing to know how to use static strap, just walk away and call your local Unicarrier dealer)before proceeding in removing the print card from unit. Disconnect battery and remove all connectors from the metal print board box. Remove card and metal housing. Carefully inspect the bus bars for any overheating and possible wire melted to them especially around the PS contactor. If all looks good then check upper right hand of the the control panel. There you will see 8 wires from 2 transistors that plugs into the upper right hand corner of the main print card. These are the IGBT's for the steering. The 530 code shows that there is a short in the PS circuit thus the inspect for melted wires. I rather see an open code ( 531 ) than the 530 short code. You can remove the cover to expose the main print card. Look upper right hand corner of card where the 8 wires comes together in a plug and is inserted into the main print card. With a mag glass, look for any small components that has blown out ( small chips ) on the card. If any are found blown then you will need a new or refurbished main print card, new set of igbt's and a ps motor check. Order the igbt's in a set from Unicarrier dealer. The reason is they are matched for same resistance reading. The ps current sensor is basically a resistor that is ceramic and is located beneath the ps contactor and it will have the Ohms value printed on it. If uncomfortable with or have never trouble shot a system as this, i would suggest calling a dealer. These parts are expensive and little wisps of smoke out of the main print board can mean over a grand in cost for a new one. The IGBT's can be costly also. Been awhile since i have worked on one of these trucks as many are being replaced by newer models. Hope this helps.