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A25c no gear select

PHDiesel ยท 2023-04-25 20:19

Hi all, Have a volvo A25C. Truck will not select any gears forward or reverse, and the alarm buzzer sounds when you try and select a gear. Contronic display unit also not working so am unable to retrieve a code Cheers

Replies11
  1. #1SlatcoAu2023-04-26 10:05

    Hmm, could be a few things. I would check and make sure that you are building full air pressure on your brake system prior to putting in gear. Another thing to check would be the rpm range when attempting to put it in gear. If you are over 900rpm it won't go into gear.

  2. #2PHDiesel2023-04-26 13:55

    truck is idling at 800rpm. Building up to 700kpa air presssure

  3. #3PHDiesel2023-04-26 13:59

    I am wondering if it is linked to the display unit not having any power, because I also found that the ECU2 which provides information to the display also has no power. Transmission ecu has 24v supply in pins 2, 20, 16 and 17, and the gear selector has power going in and out

  4. #4PHDiesel2023-04-26 15:47

    Got the contronic working, found one of the fuse holders that supplies power to ECU2 loose. Service display is showing transm.comm ER

  5. #5SlatcoAu2023-04-26 16:07
  6. #6SlatcoAu2023-04-26 16:12

    Here are some more checks

  7. #7SlatcoAu2023-04-26 16:14

    Oh boy. Been there in the past. Hope you are not going to suffer the same fate..... New to me A25C Picked up a 1997 A25C SN 5350V9574 at auction and it seems to have the typical age related issues. Just got it to my yard today, drove it around for a bit, and it upshifts/down shifts through forward gears but when backing up if you are fwd-reversing a couple times eventually it will not engage... HeavyEquipmentForums A25C Trans replacement Started on the trans replacement on my A25 this weekend. Bit of work for certain. Some takeaways for those who have not done this: - Fuel lines on my truck were similar to airbrake hose from the tank and then to a adapter fitting to some type of metric flare. I had problems finding plugs so... HeavyEquipmentForums

  8. #8PHDiesel2023-04-26 16:47

    And what was your fate?

  9. #9SlatcoAu2023-04-26 16:57

    I linked to a couple posts above. Read "New to me A25C" and then "A25C trans replacement" for details

  10. #10PHDiesel2023-04-26 17:46

    Can anyone tell me what pin on the trans ecu feeds power to sensors inside trans (turbine speed etc)

  11. #11GuzBR1232023-06-15 19:55

    Hi, allowed the problem? Does anyone have the wiring diagram for the a25c, on the a35 I was able to manually shift gears.