giving codes P1285 and P1299 need to know where the Cylinder head temperature sensor is.
Apr 12, 2023 at 12:24 PM
2006 Ford F-150 Temp Gauge Pegs
MICHELLE VANHORN
- MEMBER
- 4 POSTS
The CHT is on the rear of the LH cylinder head, just above the bellhousing. The codes you have suggest a wiring problem at the sensor. An unplugged or broken wire to the sensor will trigger both codes. I have seen them chewed off by rodents but the common issue is if the harness is pulled up so it creates a hard bend.
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Apr 12, 2023 at 6:02 PM
Do you have a video to show how to replace it? Also, is this on the front of the motor?
Apr 12, 2023 at 11:56 PM
We replaced the cylinder head temperature sensor, plugs and wires, PCV valve, oil pressure sensor/switch, upper radiator hose and the temp gauge is still pegging out in the
red but no check engine light at all and it’s not overheating because there is no water anywhere on the ground or under the hood. would the codes P1285 and P1299 be there without the check engine light on and how do
We clear them to see if the computer will reset. I need to know ASAP, please.
red but no check engine light at all and it’s not overheating because there is no water anywhere on the ground or under the hood. would the codes P1285 and P1299 be there without the check engine light on and how do
We clear them to see if the computer will reset. I need to know ASAP, please.
Apr 13, 2023 at 8:37 AM
If you replaced the sensor but still have the temp gauge issue, then it's time to check the wiring itself. A broken wire to the sensor will act the same way as a bad sensor. The easiest way to verify the wiring would be to use a meter and test the resistance between the two ends on the wires for each terminal. So, you would unplug the CHT then go to the PCM at the firewall and find the yellow wire with green trace at pin 41 and use the probes at both ends. You want to see as close to zero ohms or a beep if you have a continuity tester. Then do the same with the gray wire with red stripe at the CHT conn and terminal 58 on the PCM. I suspect it will be the first wire. To repair it will either be replacing the connector end or running an overlay wire if it's not a bad connector.
https://www.2carpros.com/articles/how-to-use-a-voltmeter
https://www.2carpros.com/articles/how-to-check-wiring
https://www.2carpros.com/articles/how-to-use-a-voltmeter
https://www.2carpros.com/articles/how-to-check-wiring
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Apr 13, 2023 at 2:59 PM
There was power to the cylinder head temperature sensor we already checked the wiring for that and then we changed the thermostat, and it fixed the problem.
Apr 13, 2023 at 8:57 PM
Good to hear, usually the thermostat would set a different code or actually show as the engine overheating.
Apr 13, 2023 at 10:37 PM
Suggested Repair
The cylinder head temperature sensor is at the rear of the left cylinder head, just above the bellhousing. P1285 and P1299 often indicate an unplugged or broken CHT wire, so check continuity from the sensor to PCM pin 41 (yellow/green) and pin 58 (gray/red) and repair the connector or overlay a damaged wire. In this case the sensor and wiring checked out, and replacing the thermostat stopped the temperature gauge from pegging in the red.
Conversation Summary
A 2006 Ford F-150 owner asked where the cylinder head temperature sensor is after codes P1285 and P1299. The expert said it is on the rear of the left cylinder head above the bellhousing and that both codes commonly come from an unplugged or broken sensor wire, including a hard bend in the harness. After the sensor, plugs, wires, and other parts were replaced, the gauge still pegged red without a check engine light or visible coolant leak. The expert advised continuity testing the CHT wires to the PCM and repairing a bad connector or wire. The owner later reported that the wiring had power and replacing the thermostat fixed the gauge problem.