joestox

What I've got:
- 1994 4runner 3vze A/T

Problem:
- REAR ANTI LOCK light comes on and stays on

Here is what I've tried:
- Reading the diagnostic codes. According to the FSM I should turn the ignition on, disconnect the service connector, and then put a jumper between Tc and E1. When I turn the ignition on the following lights appear as expected: REAR ANTI LOCK, SEATBELT, E-BRAKE, BATTERY, A/T OIL TEMP, CHECK. When I disconnect the service connector the REAR ANTI LOCK light disappears but all other lights remain. When I jumper Tc and E1 the CRUISE CONTROL light comes on and blinks twice every second. There are no diagnostics codes I can read since the REAR ANTI LOCK light remains off. Seems like I am not the only one with this issue. There is basically no way I jumped the wrong pins - I triple checked a thousand times I got the pins right. Maybe I disconnected the wrong service connector? I will post a pic of the service connector I disconnected below.

- Checked fuses. According to my owners manual there are two fuses related to the rear antilock: fuse #10 (15A fuse in driver's side kick panel) and fuse #31 (60A fuse under hood). Fuse #10 was good, but fuse #31 was missing. The previous owner had jumpered the two connecting wires across the adjacent 80A fuse. The 80A fuse was good but I replaced the 60A fuse anyways and placed the wires in their correct spots. For completeness sake I checked all the fuses in the driver's side kick box, under the hood, and (since I had the glove box out for a separate task) the ac/heater related fuses behind the glovebox. I can confirm that all fuses that I know of are now good.

- Checked the speed sensor on the rear differential. In most related threads and in the FSM it seems like a bad speed sensor could be the issue. I took the speed sensor off the rear differential, cleaned it, and check the resistance across its terminals. My meter read 621Ohms which is within the bounds specified by the FSM. I also check to see if any terminal had shorted to the body of the sensor as a second check outlined in the FSM and there was no continuity between either terminal and the body of the sensor.

Questions I have:
- How can I get diagnostic codes? Did I remove the wrong service connector?
- What should I check next? The FSM mentions that the deceleration sensor, ABS actuator, control relay are also related to the ABS system - any or all of these worth checking? Which should be prioritized?
- Any other thoughts on my predicament?


Here is the service connector that I disconnected. It's on the passenger side in the back left corner. Is this the right one?

joestox

Ok everyone, all sagas must come to an end at some point - and this one has. I found a solution. Posting here for all past/current/future 2nd gen 4Runner lovers in the same situation.

The problem was a bad ABS module. Since this is the brains behind the ABS system it makes sense that I wasn't able to read any codes and wonky things were happening like the CRUISE light flashing when I tried to read the ABS codes. I was very diligent with instructions so this was definitely odd but it makes sense in retrospect that a bad ABS brain was causing this behavior. I took the ABS module out from behind the glove compartment and opened it up. Well guess what I found. A bunch of burnt up components - mainly one of the capacitors was fried. I bought a new one on eBay for $29.00 and soon as I installed it and turned the ignition the REAR ANTI LOCK light starting behaving properly (according to the FSM it should turn on for 2 seconds when turning the ignition and then disappear).

Love a good fix!

87-4runner

Good job and thank you for posting your outcome for future enthusiasts to reap the benefit of your hard work