limp mode
09-22-2017, 09:57 AM
#1
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limp mode I have a 02 5.3 in a 94 chevy truck. I did a cam change and stall converter. the truck has been tuned. my problem is it is in limp mode. I have replaced the peddle position sensor. I can unplug the throttle body sensor and it will reset for a few min.
09-22-2017, 03:03 PM
#2
Do you have a OBDII port to read/delete the engine codes?
A '94 would need to have one installed, OBDII was in effect in '96.
On my 2003 Silverado with a 4.8 (DBW), I started the engine one morning
and the dash was displaying a reduced engine power mode. I looked in the
engine compartment and a rodent had chewed most of the wires from the
fuse box to the TAC module. I repaired the wiring including two gray wires,
which I thought were both 5V. It turns out one was 36V and one was 5V,
which were switched and this still caused P0120, P0220, P1516, P2135 codes.
Regardless of DBC/DBW, an error in the wiring could cause reduced engine
power mode. If OBDII code reading is available, this will narrow it down.
Recently, I starting getting P2135, P0120, and after replacing the throttle
body, TAC module and alternator, I was still getting a P2135. The engine
also wouldn't idle. So I did some research, and this pointed to the MAF
and/or MAP outputting erroneous data, although there were no MAF or
MAP engine codes being thrown. I replaced both and the codes are gone.
A '94 would need to have one installed, OBDII was in effect in '96.
On my 2003 Silverado with a 4.8 (DBW), I started the engine one morning
and the dash was displaying a reduced engine power mode. I looked in the
engine compartment and a rodent had chewed most of the wires from the
fuse box to the TAC module. I repaired the wiring including two gray wires,
which I thought were both 5V. It turns out one was 36V and one was 5V,
which were switched and this still caused P0120, P0220, P1516, P2135 codes.
Regardless of DBC/DBW, an error in the wiring could cause reduced engine
power mode. If OBDII code reading is available, this will narrow it down.
Recently, I starting getting P2135, P0120, and after replacing the throttle
body, TAC module and alternator, I was still getting a P2135. The engine
also wouldn't idle. So I did some research, and this pointed to the MAF
and/or MAP outputting erroneous data, although there were no MAF or
MAP engine codes being thrown. I replaced both and the codes are gone.
Last edited by 88bruce; 03-25-2018 at 02:02 PM.
09-22-2017, 07:12 PM
#3
Limp home Usually when a swap goes to the limp mode it's a mismatch between hardware and software. My '03 LM4 swap had all OEM hardware and later I found out the tune was '05. Car would rev just fine in the garage and drive fine under about 30 percent throttle but failed to limp above that. Needed a new 05 throttle peddle to solve the problem.
