CAT 64 Fault Code: Very High Intake Manifold Air Temperature
Also called High Intake Manifold Air Temperature Warning, High/Very high intake manifold air temperature
Very High Intake Manifold Air Temperature · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
CAT code 64 means the ECM has detected the intake manifold air temperature at or above 90 °C (194 °F) or, in a more severe version, at or above 110 °C (230 °F), while the engine has been running for at least 30 seconds and coolant temperature is typically above 99 °C (210.2 °F). CAT flags this as a critical event, not an electronic system fault, so it points to an actual overheating condition in the intake air, not just a bad sensor by default.
Critical severity. CAT explicitly labels this diagnostic code a critical event. Very high intake manifold air temperature combined with high coolant temperature can lead to engine damage if the machine keeps running under load. Treat this as a stop-and-inspect situation, not something to run through the shift.
What does CAT error code 64 mean?
Code 64 fires when the ECM sees intake manifold air temperature reach or exceed 90 °C (194 °F), or in some versions 110 °C (230 °F), after the engine has been running for at least 30 seconds. Several versions of this code also require engine coolant temperature to be above 99 °C (210.2 °F) or 99 °C (210 °F) at the same time, and some require the high intake air temperature to persist for more than four seconds (at the 90 °C threshold) or more than two seconds (at the 110 °C threshold).
Intake manifold air temperature matters because hot compressed air entering the cylinders reduces the engine's ability to control combustion temperatures and can accelerate thermal stress on pistons, valves, and the turbo/charge air system. CAT is specific that this code represents a real thermal event in the engine, not a wiring or sensor glitch by default, which is why it carries critical status.
Because coolant temperature is tied to several versions of this trigger, code 64 often shows up alongside general engine overheating, not as an isolated intake sensor problem.
What triggers a CAT 64 code?
The ECM sets this code when the engine has run for at least 30 seconds and intake manifold air temperature is at or above 90 °C (194 °F) (persisting more than 4 seconds in some versions) or at or above 110 °C (230 °F) (persisting more than 2 seconds in some versions). Several versions also require engine coolant temperature above 99 °C (210 °F) or 99 °C (210.2 °F) at the same time.
Common causes of 64
- Sensor failure at the intake manifold air temperature sensor
- Damaged, corroded, or loose sensor connector or wiring harness
- Poor connection at the ECM or in the harness between the sensor and the ECM
- Low engine coolant level
- Debris buildup or restricted air flow through the charge air cooler
- Heavy load on the engine combined with high ambient air temperature
How to troubleshoot CAT 64: first checks
- Check engine coolant level and top off if low; low coolant is listed as a direct cause of this code
- Inspect the charge air cooler for debris, dirt, or restricted air flow and clean it if blocked
- Look at current operating conditions: is the engine under heavy load in high ambient temperature? If so, reducing load may bring temperatures down
- Inspect the intake manifold air temperature sensor and its connector for corrosion, looseness, or physical damage
- Check the wiring harness between the sensor and the ECM, and the connection at the ECM itself, for damage or poor contact
- If connections and coolant look fine, test or replace the intake manifold air temperature sensor since sensor failure is a listed cause
How the code clears
No separate clearing step is listed for this code. Since CAT identifies this as a critical event tied to an actual thermal condition rather than a simple electronic fault, the code should clear on its own once intake manifold air temperature and coolant temperature return to normal, following inspection and repair of the underlying cause.
Affected models and serial ranges
64 appears in our records across 4 CAT models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| C11 | Serial range not listed in source records |
| C13 | Serial range not listed in source records |
| C15 | Serial range not listed in source records |
| C18 | Serial range not listed in source records |
Frequently asked questions
What does CAT fault code 64 mean?
It means the ECM has detected intake manifold air temperature at or above 90 °C (194 °F), or at or above 110 °C (230 °F) in more severe versions, after the engine has run for at least 30 seconds. Many versions also require coolant temperature above 99 °C (210 °F).
Is CAT code 64 serious?
Yes. CAT specifically labels this diagnostic code a critical event. It reflects an actual overheating condition in the engine's intake air and coolant system, not just a faulty sensor, so it should be treated as urgent.
Can low coolant cause fault code 64?
Yes. Low engine coolant level is directly listed as a probable cause of this code, since it contributes to the engine coolant temperature climbing above the threshold tied to this fault.
Can a dirty charge air cooler trigger this code?
Yes. Debris or restricted air flow through the charge air cooler is listed as a probable cause, since it reduces the cooler's ability to bring intake air temperature down before it enters the manifold.
Does heavy load or hot weather affect this code?
Yes. Heavy load on the engine combined with high ambient air temperature is listed as a probable cause, since both increase the heat load the intake and cooling systems have to manage.
Is fault code 64 always a sensor problem?
No. CAT notes this code does not represent an electronic system fault by default. While sensor failure, connector issues, and harness problems are listed causes, low coolant, a dirty charge air cooler, and heavy load in hot conditions are also listed causes.
Which CAT engines can show fault code 64?
This code applies to the C11, C13, C15, and C18 engine models.