Description

Hyundai A5SR2 Service Manual – Factory Specs for JATCO 5-Speed Transaxle

If you’re cracking open a JATCO A5SR2 transaxle from a Genesis Coupe or a Grand Starex (H-1) and you don’t have the OEM manual on your bench, you’re gambling with a valve body that costs as much as a used Civic. I’ve seen techs throw parts at a 5-speed that just needed a Sub ROM reset, or worse – they torque a valve body bolt with aftermarket spec and strip the aluminum. This Hyundai A5SR2 Service Manual is 16 pages of what you actually need: factory calibration data, sensor locations, and the reset procedure that aftermarket reprints leave out. No fluff, no pictures of the interior – just the transaxle.

Specification and Main Features

page 3 lists the full specification table for the A5SR2. Max torque rating is 45 kgfm (roughly 325 ft-lb). Planetary gear set is three simple epicyclic units: front, middle, rear. Six variable force solenoid valves plus one on/off. Two input (turbine) speed sensors, two output speed sensors, two oil temperature sensors – one in the pan, one at the torque converter outlet. The manual explains that this transmission was developed to handle the higher torque of the A-2.5 diesel engine, which the old Aisin FR 4-speed couldn’t take. Gear ratios: 1st 3.730, 2nd 2.308, 3rd 1.159, 4th 1.000, 5th 0.840, reverse 2.740. ATF capacity is 10 liters of Apolloil ATF RED-1. If you’re swapping a valve body, scan page 4 for the Sub ROM unit description – that little board stores the pressure-current map for each specific valve body.

Operating Element and Inputs/Outputs

pages 7-8 walk you through the operating element – basically the H-MATIC lever and the sport mode logic. The manual explicitly states that when you select sports mode from Drive while in 5th gear, the TCM automatically downshifts to 4th. That’s not a fault, it’s normal control. The inputs/outputs section (page 8) shows the wiring for the TCU, including the sport mode switch circuit. I’ve seen guys replace a TCU because they didn’t know that switch has its own diagnostic code. The manual gives you the diagnostic code reference right there.

Why the Sub ROM Procedure Matters

page 14 covers the Sub ROM unit itself. This is the part that stores the unique hydraulic compensation data for each individual valve body. If you install a used valve body without swapping the Sub ROM or re-initializing the TCM, the shift feel will be off – maybe harsh, maybe slipping. Page 15 gives the exact sequence for Sub ROM reset and TCM adaptive learning. You need a scan tool that can write to the TCM, and you have to follow the steps in order: reset the Sub ROM, then perform the adaptive learning drive cycle. Skip this and you’ll be chasing drivability complaints for a week. I keep a printout of page 15 taped to my scan tool cart.

3 Sensor Checks You Should Run First

Before you pull the pan, read page 12 (speed sensor) and page 9 (inhibitor switch). The A5SR2 uses two input speed sensors and two output sensors – that’s four speed sensor circuits total. A single failed sensor can cause a stuck-in-gear or a no-shift condition. The manual shows the resistance values and the installation gap (it’s a non-contact hall-effect type, so no gap adjustment, but the O-ring must be intact). The inhibitor switch (page 9) has its own adjustment procedure – you’ll need a 0.5 mm feeler gauge to set the neutral position. Most cheap aftermarket diagnostic trees skip this, and you end up with a misaligned switch that causes a no-crank condition in park.

Source Authenticity: This Is a Hyundai OEM Document

This manual was originally released by Hyundai Motor Company – it says copyright Hyundai and “Drive your way” on the first page. The PDF is a direct scan of the factory document, revision 1 dated 01.01.2009. Every torque value, every diagnostic step, every wiring pinout comes from the source. I won’t touch a third-party reprint for a JATCO transaxle because they always alter the Sub ROM reset sequence or omit the line pressure check (page 16). The line pressure check needs a pressure gauge and T-level of 100 psi – the manual tells you which port to use and at what engine RPM. No guesswork. For more OEM manual resources, see Automotive Industry Overview and Automotive Industry Overview.

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Does this manual have wiring diagrams for the A5SR2?

The manual covers the electrical inputs/outputs on page 8, speed sensor circuits, solenoid valve circuits, and the inhibitor switch wiring. Full pinout diagrams are not included; this is a transaxle service manual, not a vehicle wiring manual. You’ll need the vehicle-specific service manual for chassis wiring.

How do I reset the Sub ROM on an A5SR2 without a dealership scan tool?

You need a bidirectional scan tool that can perform TCM adaptive learning. The procedure on page 15: first use the scan tool to reset the Sub ROM data in the TCM. Then drive the vehicle in specific shift patterns (1st to 2nd at light throttle, 3rd to 4th at medium throttle, etc.) until the TCM completes the adaptation. This typically takes 10-15 minutes of road driving. If you skip the drive cycle, the TCM will still use old compensation values and shifts will feel wrong.

I’ve been burned by aftermarket manuals that skip the Sub ROM reset – cost me a customer who came back three times for harsh downshifts. This OEM PDF is 16 pages, but those pages will save you a transmission replacement. Access the Factory Manual from AutoRepairManuals and put it in your tablet next to the lift. You’ll thank me when the line pressure spec is right on page 16.