Can't solve P2135 mystery

[harbison]

Been dealing with this problem off and on for 2 years. I've replaced TPS Sensor 4 times, replaced pigtail (I broke one of the clips while replacing TPS), replaced MAF Sensor, cleaned Throttle Body, had dealership reprogram ECM the first time I replaced TPS Sensor.

Two weeks ago replaced TPS Sensor with AC Delco (previous ones had been AutoZone Duralast), removed and cleaned throttle body. Followed TSB to the letter.

Last night experienced "Reduced Engine Power", "Stabilitrak Off", "Service Traction Control" and Check Engine Light with P2135 code.

Pulled over, turned car off, popped the hood, closed the hood, started back up and drove home.

I haven't replaced the throttle body itself. Willing to do what it takes to keep it running.

 

[harbison]

replaced throttle body. deleted AFM with DiabloSport tuner. Still having same problem occassionally.

 

[harbison]

replaced throttle body. deleted AFM with DiabloSport tuner. Still having same problem occassionally.

This gremlin has returned again. P2135 with reduced engine power. It's happened several times in the last week. Happened yesterday when we went over the railroad tracks. I've replaced Throttle Body, TPS sensor, MAF sensor, Accelator pedal with sensor. This one has me stumped.

 

[Doubeleive]

sounds like a electrical short in your harness somewhere, maybe replace the harness from the pedal to the throttle body?

 

[swathdiver]

This gremlin has returned again. P2135 with reduced engine power. It's happened several times in the last week. Happened yesterday when we went over the railroad tracks. I've replaced Throttle Body, TPS sensor, MAF sensor, Accelator pedal with sensor. This one has me stumped.

But you haven't replaced your ECM! Your ECM contains the processors to monitor the TAC system data.

CIRCUIT/SYSTEM TESTING
1. Ignition OFF, disconnect the harness connector at the throttle body. Allow up to 2 minutes for the ECM to completely power down.
2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal C and ground.
 If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, test for 4.8-5.2 volts between 5-volt reference circuit terminal E and ground.
 If less than 4.8 volts, test 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
 If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Verify the scan tool TP sensor 1 voltage is less than 0.1 volt.
 If greater than 0.1 volt, test the signal circuit terminal D for a short to voltage. If the circuit tests normal, replace the ECM.
5. Verify the scan tool TP sensor 2 voltage is greater than 4.8 volts.
 If less than 4.8 volts, test the signal circuit terminal F for a short to ground. If the circuit tests normal, replace the ECM.
6. Install a 3A fused jumper wire between the signal circuit terminal D and the 5-volt reference circuit terminal E of the TP sensor 1. Verify the TP sensor 1 voltage is greater than 4.8 volts.
 If less than 4.8 volts, test the TP sensor 1 signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
7. Install a test lamp between the signal circuit terminal F of the TP sensor 2 and ground. The test lamp should not illuminate.
 If the test lamp illuminates, test the TP sensor 2 signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
8. Install a 3A fused jumper wire between the signal circuit terminal F and the low reference circuit terminal C of the TP sensor 2. Verify that the TP sensor 2 voltage is less than 0.1 volt.
 If greater than 1.0 volt, test the TP sensor 2 signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
9. Ignition OFF, disconnect the harness connector at the ECM.
10. Test for less than 5 ohms on all TP sensor circuits between the following terminals:
 ECM X2 signal circuit terminal 57 to TP terminal D
 ECM X2 signal circuit terminal 59 to TP terminal F
 ECM X2 5-volt reference circuit terminal 53 to terminal E
 If greater than 5 ohms, repair the affected circuit for open/high resistance.
11. Test for infinite resistance between TP sensor 1 signal circuit terminal D and TP sensor signal circuit terminal F.
 If less than infinite resistance, repair the short between TP sensor 1 signal circuit and TP sensor 2 signal circuit.
12. If all circuits test normal, replace the throttle body.

 

[harbison]

swathdriver, thanks for the detailed diagnostics. I will test the ECM.

 

[sumo]

Don’t replace. Look for this bulletin 11-06-04-007c

 

[harbison]

sumo I can't find tsb 11-06-04-007c but I have been through 11-06-04-007b which is throttle position sensor replacement. I believe c is just an updated version to include 2011 models.

 

[sumo]

Hmm. I didn’t see that part where you had dealer reprogram. I’m wondering if you have a intermittent short in your harness or a soft set pin connection issue on your connector. Did you inspect the connector and see if you had any corrosion or misaligned pins?

 

[harbison]

sumo

Hmm. I didn’t see that part where you had dealer reprogram. I’m wondering if you have a intermittent short in your harness or a soft set pin connection issue on your connector. Did you inspect the connector and see if you had any corrosion or misaligned pins?

Are you referring to the harness or soft set pin connection on the ecm? I personally haven't checked the ecm yet.