Drive Engine Run-Up (DERU) Load Test
WARNING: This page is about a different car, the 2004 Mazda Tribute, 2003 Mazda Tribute, and 2002 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
Block the front and rear wheels, and apply the parking brake and the service brake, or injury to personnel can result.
CAUTION:
Do not carry out the Engine Load Test for more than five seconds or damage to the transaxle or transaxle can result.
To carry out this test, proceed as follows:
- Block the front and rear wheels.
- Apply the parking brake and the service brake.
- Install a tachometer.
- Shift the transaxle into Drive, and increase and decrease the engine RPM between an idle to approximately 2000 RPM. Note the engine RPM and, if possible, determine the vibration frequency.
- Repeat the test in Reverse.
- If the vibration or noise is duplicated when carrying out this test, inspect the engine and transaxle or transaxle mounts.
- If the concern is definitely engine speed-related, carry out the Engine Accessory Test to narrow down the source. See ENGINE ACCESSORY TEST .
- Proceed as necessary.