Grade Logic Control Explained (HSN 0603-01)

Publication date: 2003-06-01
Reference number: HSN 0603-01

GRADE LOGIC CONTROL EXPLAINED

TECHNICAL SERVICE BULLETIN

Reference Number(s): HSN 0603-01, Date of Issue: June 1, 2003

HONDA:	1994-2003 Accord; 1996-2003 Civic; 1997-2003 CR-V; 2003 Element; 1995-2003 Odyssey 2003 Pilot; 1997-2001 Prelude
CATEGORY:	Honda Service News
APPLIES TO:	1994 - 2003 Accord, 1996 - 2003 Civic, 1997 - 2003 CR-V, 2003 Element, 1995 - 2003 Odyssey, 2003 Pilot, 1997 - 2001 Prelude

SERVICE INFORMATION

NOTE: This article applies to A/T-equipped '94 - 03 Accords, '96 - 03 Civics, '97 - 03 CR-Vs, '03 Elements, '95 - 03 Odysseys, '03 Pilots, and '97 - 01 Preludes.

Grade Logic Control in the PCM keeps the A/T from making frequent shifts when you're going up or down a hill, or going around corners. The vehicle can ride more smoothly and have more power when it's needed. The PCM adjusts the shift points by comparing actual driving conditions based on input from the vehicle speed sensor, throttle position sensor, and engine coolant temperature sensor, along with the brake switch signal and the shift lever position signal to the values stored in the PCM memory.

ASCENDING CONTROL

When the PCM determines that you're climbing a hill with the shift lever in a D (drive) position (shift lever position names vary by model and model year), Grade Logic Control may delay upshifting from 2nd to 3rd gear, 3rd to 4th gear, and from 4th to 5th gear (if you've got a 5-speed A/T), to keep the A/T from shifting too soon or too often.

DESCENDING CONTROL

When the PCM determines that you're going down a hill with the shift lever in a D (drive) position (shift lever position names vary by model and model year), Grade Logic Control may delay upshifting from 2nd to 3rd gear, 3rd to 4th gear, and from 4th to 5th gear (if you've got a 5-speed A/T), to keep the A/T from shifting too soon or too often. This shift pattern and deceleration lockup help control your speed so you don't need to brake. If you do need to brake, Grade Logic Control may downshift the A/T from 5th to 4th gear (if you've got a 5-speed A/T), 4th to 3rd gear, or 3rd to 2nd gear, depending on how steep the hill is, how fast you're going, and how fast you're decelerating.

DECELERATION CONTROL

When going around corners, the vehicle needs to decelerate first and then accelerate. Grade Logic Control anticipates corners when you're decelerating from speeds above 27 mph and reduces the number of gear shifts.

Want more info about Grade Logic Control? Refer to section 14 of the appropriate S/M.