MC775
Newbie
Hello everyone!
From several days I'm the owner of 2 doors 1997 Chevrolet Tahoe 4WD powered by 6,5 TD. I bought it broken - previous owner told me that the transmission is broken and the car can only drive at the 1st and reverse gears. After an inspection and some tips from a different forum it turned out that an electronic injection pump in my Tahoe has been replaced with a mechanical one. I've read something about this procedure yesterday, and now my suspection is that the problem is in this modification, not in the transmission itself. Symptoms: MIL light is on, and it seems that car is in a limp mode: it only drives on 1st and reverse gears.
In a shortcut:
1. I pulled out OBD codes, list below.
2. There is a loose bunch o wire harnesses at the top of the engine, probably used for electronic injection pump.
3. There are some modifications made to the big wire harness at the back of the engine, some wires are cut and connected with the wires from loosy harnesses.
4. APP is replaced with a pedal with a cable that goes to the injection pump.
5. Nothing else looks like it was modified.
Today:
1. I re-soldered all modified connections on the big wire harness, old connections were old and rusty.
2. I checked the crank sensor, it has correct impedance.
3. I disconnected plugs from the transmission and cleaned them up, all were rusty.
4. I cleaned some other rusty electric connectors.
Unfortunately it didn't help
I'm looking for some information about this modification, especially about how was the PCM forced to work with mechanical injection pump. In a GM service manual I found that 3 faulty APP sensors will cause PCM to put the car into a limp mode. As you can see at the list of my codes, there are 3 codes for APP. Of course there are no APP sensors in my car since it was modified for mechanical injection pump, so how was the PCM "fooled"?
I will be very grateful with any help from you.
Codes list:
From several days I'm the owner of 2 doors 1997 Chevrolet Tahoe 4WD powered by 6,5 TD. I bought it broken - previous owner told me that the transmission is broken and the car can only drive at the 1st and reverse gears. After an inspection and some tips from a different forum it turned out that an electronic injection pump in my Tahoe has been replaced with a mechanical one. I've read something about this procedure yesterday, and now my suspection is that the problem is in this modification, not in the transmission itself. Symptoms: MIL light is on, and it seems that car is in a limp mode: it only drives on 1st and reverse gears.
In a shortcut:
1. I pulled out OBD codes, list below.
2. There is a loose bunch o wire harnesses at the top of the engine, probably used for electronic injection pump.
3. There are some modifications made to the big wire harness at the back of the engine, some wires are cut and connected with the wires from loosy harnesses.
4. APP is replaced with a pedal with a cable that goes to the injection pump.
5. Nothing else looks like it was modified.
Today:
1. I re-soldered all modified connections on the big wire harness, old connections were old and rusty.
2. I checked the crank sensor, it has correct impedance.
3. I disconnected plugs from the transmission and cleaned them up, all were rusty.
4. I cleaned some other rusty electric connectors.
Unfortunately it didn't help
I'm looking for some information about this modification, especially about how was the PCM forced to work with mechanical injection pump. In a GM service manual I found that 3 faulty APP sensors will cause PCM to put the car into a limp mode. As you can see at the list of my codes, there are 3 codes for APP. Of course there are no APP sensors in my car since it was modified for mechanical injection pump, so how was the PCM "fooled"?
I will be very grateful with any help from you.
Codes list:
Car Scanner ELM OBD2
DTC report
Selected brand: Chevrolet
============1==============
P0601
Raw code: 0601
ECU: 10
Status: Pending
OBDII: Engine control module (ECM) - memory check sum error
============2==============
P0601
Raw code: 0601
ECU: 10
Status: Confirmed
OBDII: Engine control module (ECM) - memory check sum error
============3==============
U1000
Raw code: D000
ECU: 10
Status: Pending fault present, Pending fault present during this driving cycle, Test is inhibited by other DTC, Test has not been completed, Validated fault present at time of request
OBDII: Class 2 Communication Malfunction
============4==============
P1218
Raw code: 1218
ECU: 10
Status: Pending fault present, Pending fault present during this driving cycle, Test conditions are met, Test is inhibited by other DTC, Validated and stored in non volatile memory
OBDII: CID High
Chevrolet: Injection Pump Calibration Circuit
============5==============
P0601
Raw code: 0601
ECU: 10
Status: Pending fault present, Pending fault present during this driving cycle, Test conditions are met, Test is inhibited by other DTC, Test has not been completed, Validated and stored in non volatile memory, Validated fault present at time of request, Validated fault has been present during this drive cycle
OBDII: Engine control module (ECM) - memory check sum error
============6==============
P0228
Raw code: 0228
ECU: 10
Status: Pending fault present, Pending fault present during this driving cycle, Test conditions are met, Test is inhibited by other DTC, Test has not been completed, Validated and stored in non volatile memory, Validated fault present at time of request, Validated fault has been present during this drive cycle
OBDII: Throttle position (TP) sensor C/accelerator pedal position (APP) sensor C - high input
============7==============
P0223
Raw code: 0223
ECU: 10
Status: Pending fault present, Pending fault present during this driving cycle, Test conditions are met, Test is inhibited by other DTC, Test has not been completed, Validated and stored in non volatile memory, Validated fault present at time of request, Validated fault has been present during this drive cycle
OBDII: Throttle position (TP) sensor B/accelerator pedal position (APP) sensor B - high input
============8==============
P0215
Raw code: 0215
ECU: 10
Status: Pending fault present, Pending fault present during this driving cycle, Test is inhibited by other DTC, Test has not been completed, Validated and stored in non volatile memory, Validated fault present at time of request
OBDII: Fuel shut-off solenoid - circuit malfunction
============9==============
P0122
Raw code: 0122
ECU: 10
Status: Pending fault present, Pending fault present during this driving cycle, Test conditions are met, Test is inhibited by other DTC, Test has not been completed, Validated and stored in non volatile memory, Validated fault present at time of request, Validated fault has been present during this drive cycle
OBDII: Throttle position (TP) switch A/accelerator pedal position (APP) switch A - low input
============10==============
P0601
Raw code: 0601
ECU: 10
Status: Pending
OBDII: Engine control module (ECM) - memory check sum error
============11==============
P0601
Raw code: 0601
ECU: 10
Status: Confirmed
OBDII: Engine control module (ECM) - memory check sum error
============12==============
P0601
Raw code: 0601
ECU: 10
Status: Pending
OBDII: Engine control module (ECM) - memory check sum error
============13==============
P0601
Raw code: 0601
ECU: 10
Status: Confirmed
OBDII: Engine control module (ECM) - memory check sum error