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Re: Anti-lock problems code 1222 help!! Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Fri, 18 Jan 2008 06:16:49
In Reply to: Anti-lock problems code 1222 help!!, mcemu, Thu, 17 Jan 2008 12:58:40 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Fault code 1222 is "Faulty main valve, broken/short-circuit in the valves wiring harness, or faulty ECU."
I shall now do a selected reading from the Saab ABS Diangostic Procedures, Section 5, page 2. All rise:
1. Check the wiring and the Main Valve for continuity by measuring the resistance between pin 18 on the ECU and ground. The resistance should be 2 to 5 ohms. If not:
A. Check the wiring harness for continuity between pin 18 and pin 1 on the Main Valve connector.
B. Check for continuity through the Main Valve by measuring the resistance between pin 1 and pin 2 on the Main valve block. The resistance should be 2-5 ohms. If not, replace the main valve.
C. Check for continuity between pin 2 on the Main Valve and the grounding point on the Hydraulic Unit.
2. Erase the fault code and test drive to see if the fault code returns.
3. If the fault code returns, fit a new ABS ECU. (What they don't say is that if you didn't get continuity, FIX IT.)
AMEN.
OK, that said, what's up? First, it's probably not the ABS ECU. My first guess is a bad ground or a poor connection at the connector. Second, and much farther down on the list, is a flaky Main Valve.
Find the main valve. It's mounted right on the ABS assembly (thing with the reservoir and the accumulator [black sphere]). Look for a 2 pin connector, probably facing the front of the car. Make sure the ground wire (pin 2, black) goes to ground. Pull the screw off holding it to ground, and brighten up the surfaces, and bolt back down. Pop the connector off the Main Valve, and squirt it with some contact cleaner. Let dry and reinstall. Then take it back on and off a couple of times - this wiping action helps clean the contacts. Pop the connector off the ABS unit, squirt with cleaner, let dry, and re-install.
Clear the codes and see if you've fixed the problem.
My guess is that you've got a marginal ground contact. When things warm up, the resistance increases. You go from a good-enough contact to a not-good-enough contact and the ABS system throws a fault. A poor electrical contact in the engine compartment of a 15-year old car isn't unheard of. Also, inspect the wiring from the ECU to the Main valve (pin 1, green/red wire) to make sure it isn't shorting to ground.
After that, it could be a bad Main Valve. The coil inside may be getting tired and the resistance increases out of range when warmed up, or it develops and open circuit when it warms up and expands. That would require replacing the main valve. If you send me an email with your email (hit my name up by the Posted by), I can send you some documentation.
I'll bet it's just a bad connection.
Good luck.
posted by 192.249....
, Fri, 18 Jan 2008 06:16:49 <-- Viewing This Message, Mon, 21 Jan 2008 13:55:52
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