Code 41,42, 65
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From: OKC
Code 41,42, 65
Check engine light came on the other day, so I pulled a KOEO and get a 41 (lean) in memory (hard fault 11, normal). So I run KOER and I get codes 42 (rich) and 65 (Intermit HO2S, signal or ground). Should I drive it anywhere, I see black smoke coming from the exhaust, esp when I either goose it or accelerate hard and the exhause smell like #$#$#$. Then after about three miles the check engine light comes on again (code 41). Just idealing in the drive it will show rich black smoke when goosed and in a short time the check engine light comes on again.
What gets me is I have replaced the HO2 sensor about a year ago as routine maintenance. Of course I threw the old one away (wrong). I would again replace it but that is just chasing parts at about $45.
Looking for comments so I don’t chase parts on this one.
Fully Standard 351, full size Bronco, Auto. Have replace TSP, H02, cleaned Throttle plates and EGR value all within the last two years (110, 000 miles
What gets me is I have replaced the HO2 sensor about a year ago as routine maintenance. Of course I threw the old one away (wrong). I would again replace it but that is just chasing parts at about $45.
Looking for comments so I don’t chase parts on this one.
Fully Standard 351, full size Bronco, Auto. Have replace TSP, H02, cleaned Throttle plates and EGR value all within the last two years (110, 000 miles
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Code 41,42, 65
Mena, I think the code 65 is the key to your problem; it signals that the engine isn't going into closed loop. That would explain the O2 sensor codes, and the rich running.
The first thing to check is the coolant temperature sensor. Try removing and cleaning it first. You can check it with a multimeter, but I don't remember the values to look for. Do a forum search, and you'll find a lot of info on them.
Also check the connector to the O2 sensor. Sometimes the heat will cause a poor wiring connection.
The first thing to check is the coolant temperature sensor. Try removing and cleaning it first. You can check it with a multimeter, but I don't remember the values to look for. Do a forum search, and you'll find a lot of info on them.
Also check the connector to the O2 sensor. Sometimes the heat will cause a poor wiring connection.
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From: OKC
Code 41,42, 65
Thanks, forgot to say it is a 90 Bronco. Will check coolant sensor today and check my Haynes book for resistance. Won't I get a code on it (coolant sensor??) I have already removed and inspected the O2 sensor and wiring. Probaby need to check wiring up close to the engine.
I am under the impression that after 10 years and 100,000 miles most sensors should be replaced "just because."
I am under the impression that after 10 years and 100,000 miles most sensors should be replaced "just because."
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Code 41,42, 65
Yeah, a bad ECT should show a code 51 or 61. My thoughts were that the temp sensor had corroded over time and lost it's ground. It may or may not show up as a code. It's one of the sensors that causes the engine to go into closed loop when it gets warm, that's why I suggested it. Also the fact that the CEL comes on only after 3 miles; that's about the right time for it to come out of warm-up mode.
I think all the codes are related. The 65 means it's not going into closed loop, and the 41 and 42 points to a non-working O2 sensor. Hard to say which is causing which. Ordinarily I would suggest replacing the O2 sensor, if it wasn't so new.
You don't have a second O2 sensor on that engine, do you?
I think all the codes are related. The 65 means it's not going into closed loop, and the 41 and 42 points to a non-working O2 sensor. Hard to say which is causing which. Ordinarily I would suggest replacing the O2 sensor, if it wasn't so new.
You don't have a second O2 sensor on that engine, do you?
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From: OKC
Code 41,42, 65
No second O2-the only one is in the x-over between right/left pipes. I replaced coolant sensor with a new one but no luck (was just $18) but the NAPA guy also thinks it is the O2 sensor (or he was just trying to sell me one). So now either I check voltages on the O2 and just pay my $50 and take my chances. Teach me to throw away old parts.
Thanks for your reply and help.
Thanks for your reply and help.
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From: Gateway to the West
Code 41,42, 65
If Code 65 = INTERMITTENT signal or ground HEGO sensor....check the connector and harness to the sensor while you are under there....lousy conductivity will cause "intermittent" operation. That connector is down under the truck exposed to all sorts of crud and temperature fluctuations. The problem may be a simple electrical/resistance issue. Wouldn't be the first time a filthy ground connection wreaked havoc on a computer. If the computer is only getting signal once in a while it can't make the necessary adjustments to the fuel/air and spark parameters to keep the truck from running rich OR lean. Hence you have BOTH a "rich" code and a "lean" code showing. Computer can't make up its mind because its not getting the whole story.
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From: OKC
Code 41,42, 65
Thanks to all--I have done a good inspection and it looks good. I traced it up to around the battery (pass side). I see there is another connector, so maybe I should pull that connector and test the circuit/wires from up top to below and ensure this path has continuity. Was gone most of the three day holiday. I really hate thinking of testing the circuit all the way back to the computer.
BUT---is code "65" really a bad O2 connections??? I have seen pages with 65 as something like "key voltages low" and Auto Zone tells me it concerns the overdrive switch. So now I am confused. Having a co-worker bring the ford shop manual for the beast.
BUT---is code "65" really a bad O2 connections??? I have seen pages with 65 as something like "key voltages low" and Auto Zone tells me it concerns the overdrive switch. So now I am confused. Having a co-worker bring the ford shop manual for the beast.
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Code 41,42, 65
Mena, the code 65 can mean 3 different things, according to the vehicle type.
1. Charging system problem; voltage over 17.5v.
2. Engine control system never went into closed loop fuel operation.
3. Transaxle problem; OCS (Overdrive Cancel Switch) was not cycled during engine run self-test.
You don't have a transaxle; disregard #3. If it charges OK, then disregard #1. That leaves #2; constant open loop operation. (This would coincide with a bad/no signal return) sensor.)
When the codes are scanned, the first one(s) to show up are usually the culprits. Later codes can be the result of earlier ones. The later ones will usually disappear once the trouble is found. I suspect you have another bad O2 sensor, or possible connector or wiring issues.....
1. Charging system problem; voltage over 17.5v.
2. Engine control system never went into closed loop fuel operation.
3. Transaxle problem; OCS (Overdrive Cancel Switch) was not cycled during engine run self-test.
You don't have a transaxle; disregard #3. If it charges OK, then disregard #1. That leaves #2; constant open loop operation. (This would coincide with a bad/no signal return) sensor.)
When the codes are scanned, the first one(s) to show up are usually the culprits. Later codes can be the result of earlier ones. The later ones will usually disappear once the trouble is found. I suspect you have another bad O2 sensor, or possible connector or wiring issues.....
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