P0218
Transmission Fluid Over Temperature Condition
When a vehicle powertrain module registers the fault code P0218, it points directly to an internal system malfunction identified as "Transmission Fluid Over Temperature Condition". Operating your engine under this condition may degrade long-term fuel maps.
Driver's Summary
Your vehicle's computer logged P0218 after detecting a malfunction in the transmission fluid over temperature condition system. The most common signs are transmission warning light, harsh shifting, slipping, burning smell. Stop driving as soon as it is safe to do so. This fault can lead to expensive secondary damage if left unaddressed.
Symptoms
Transmission warning light, harsh shifting, slipping, burning smell
Common Causes
- Towing heavy loads in overdrive
- Clogged transmission cooler lines
- Low transmission fluid
- Internal transmission friction/slipping
How to Fix
- 1 Stop and let transmission cool, turn off O/D when towing
- 2 Flush and clean transmission cooler
- 3 Top off transmission fluid
- 4 Overhaul transmission if internally damaged
Technical Explanation
P0218 is stored after the control module confirms the fault over multiple ignition cycles, ruling out transient electrical noise as the cause. For injector-specific codes, the ECM monitors the injector control circuit voltage drop during each pulse; a shorted or open injector presents a characteristic resistance signature that differs measurably from a healthy unit. After two failed drive cycles, the code transitions from a pending to a confirmed DTC, and the PCM activates the MIL. Clearing the code without repairing the fault will result in re-illumination within one to two complete drive cycles.
Is It Safe to Drive?
Driving with an active P0218 fault risks accelerating damage to towing heavy loads in overdrive and related components. The longer the fault persists, the more expensive the eventual repair becomes — what starts as a sensor or solenoid issue can escalate to major mechanical failure.
Mechanic's Pro Tip
When diagnosing P0218, start with the cheapest and most accessible potential causes first: verify fuses, relay operation, and connector integrity before purchasing any parts. Use a scan tool to capture live data during the fault condition — static readings with the fault absent often yield no useful information. Document the freeze frame data stored with the code; it records the exact engine conditions (RPM, load, coolant temp, fuel trim) at the moment the fault was detected and is invaluable for replicating the fault on a test drive.
Cooler flush: 150; Transmission rebuild: 2,000 - 3,000+