Resposta para "Why does engine rev up and down when I step on brake?"I was able to fix this problem when it happened to my 1988 Toyota Custom Cab - 3VZ-E V-6 engine - standard transmission - no cruise control. If you have access to the 1988 Toyota Electrical Wiring Diagram manual, you can find the circuit that's giving you the problem on page 28 (TCCS section 6-1). You start at a 15 amp fuse (15A STOP) that feeds the STOP brake light switch (brake switch). You go through the switch, to connector N5 terminals 4 & 5 (you can check your brake switch function here - 8-14 volts when the brake is applied). You go through N5 and end up at the TCCS ECU module (Toyota Control Computer System - Engine Control Unit) terminal STP-6 under the dash on the passenger side. This STOP brake light switch wire is not the one that activates your brake lights - it feeds a signal to the TCCS that tells the (AUTOMATIC) transmission to reset to idle and prep to go into 1st gear. I have a MANUAL transmission - and every stop light I came to, sitting there with my brakes on, would rev the engine up...
Resposta para "Why does engine rev up and down when I step on brake?"I own a 1988 4X4, with 6 cylinder 3VZE engine and a Manual (Standard) transmission without Cruse Control. The answer lies on p.28 of the Toyota Electrical Wiring Diagram Manual. I was able to clip and tape (1) wire to cure the problem. My truck would rev up like I was maxing the gas at every stop light. As soon as I got off the brake, everything would go back to normal. I was looking at replacing my $1000 TCCS module but it cured the problem. If you have an Automatic transmission with Cruse Control it won't work.