ECT Code 21..Still!
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Postmaster
Joined: Jun 2004
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From: B/CS, Texas!!
ECT Code 21..Still!
Hey guys... I have this pesky problem. I keep getting Code 21, ECT out of Self-Test Range, on KOER. It passes KOEO, but no matter how warmed-up the engine is, Code 21 always shows. I replaced the ECT sensor, but it still shows. Yea, codes have been cleared.
Im now thinking that the coolant really isn't getting warmed up. What could cause that? A bad t-stat? Thanks!
Im now thinking that the coolant really isn't getting warmed up. What could cause that? A bad t-stat? Thanks!
Post Fiend
Joined: Nov 2001
Posts: 14,947
Likes: 6
From: Topsfield, MA
A bad t-stat would either keep it open or closed. Open means the coolant is in constant circulation and over-cooling the engine making it not arrive at proper engine temp. Close - it would overheat. Verify that the coolant is reaching approximately 180-195 degrees.
Check for the 5v reference voltage at the TPS sensor, this verifies that the ECA 5v reference is working. If so, check the resistance of the ECT. At normal operating temp the resistance should be 2800 ohms + or - about 1000 (it ranges from 60,000 to 1100).
If the resistance is ok, with the sensor disconnected, put a voltmeter on the signal wire, you should see 5v. If not, repair the defective wire or connection at the ECA.
If it does read 5v, leave the sensor wire connected and connect a jumper wire between the ECT sig wire and the sig rtn wire at the ECT connector. If it doesn't go to 0, repair the sig rtn wire. If it does, replace the ECA.
I'm gonna say you probably have a bad wire/connection between the ECT and computer. I'd look there first...
Hope that helps.
Check for the 5v reference voltage at the TPS sensor, this verifies that the ECA 5v reference is working. If so, check the resistance of the ECT. At normal operating temp the resistance should be 2800 ohms + or - about 1000 (it ranges from 60,000 to 1100).
If the resistance is ok, with the sensor disconnected, put a voltmeter on the signal wire, you should see 5v. If not, repair the defective wire or connection at the ECA.
If it does read 5v, leave the sensor wire connected and connect a jumper wire between the ECT sig wire and the sig rtn wire at the ECT connector. If it doesn't go to 0, repair the sig rtn wire. If it does, replace the ECA.
I'm gonna say you probably have a bad wire/connection between the ECT and computer. I'd look there first...
Hope that helps.
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