P0135 and P0155 '97 K2500 driveability

[twavor]

Hey guys,

Got a 97 GMC sitting here in the shop, and it's got me pulling my hair out. Got a 350 in it, and it all of a sudden started falling on it's face from a stop, especially when pulling a trailer. I can duplicate the problem by just putting the pedal to the floor at takeoff and it will cough and sputter and backfire like a wet distributor cap for about one second and then it takes off and seems to run fine, but I'd almost say it's a little low on power.

 

Checked for codes, got the P0135 and the P0155 for both front O2 sensor heater circuits, cleared them, and they will come back pretty quick. I've replaced the cap and rotor, checked the plug wires and the plugs have about 5000 miles on them. No misfires show up on my Genisys scanner either.

 

Pretty sure that I've got a wiring problem, possibly a faulty PCM since both the O2 sensor codes show up at the same time. Basically, just want to run this past you guys and see if anyone else has any ideas that I'm not thinking of, any trouble spots you've ran across, or has anyone had a similar problem. The cam sensor and MAF sensor seem to be on the same circuit from what I can tell. I haven't got the best wiring diagram, so if anyone can find mine or can lead me to one I'd appreciate it. Thank you in advance for any and all help!

 

Travis

[CRTurboGuy]

Have you replaced the fuel filter? I get something similar every couple years w/ my Jimmy, and a fuel filter change usually fixes it.

 

--JOsh

[twavor]

Have you replaced the fuel filter? I get something similar every couple years w/ my Jimmy, and a fuel filter change usually fixes it.

 

--JOsh

 

Yep, one of the first things I always check. It was clear, but it had been on there about a year and a half, so I replaced it. I'm a stickler about those.

The more I mess with this thing, I'm almost suspecting watered down gas, but it's been doing it for too long and I just don't think so.

 

Travis

[00Silverado4x4]

What about those O2 sensors? If your truck is throwing the codes for them, did you take them out and check them? If you just cleared the codes and didn't check you could be overlooking the very problem. If they are good then yes I'd definitely be looking over all your wires.

[twavor]

What about those O2 sensors? If your truck is throwing the codes for them, did you take them out and check them? If you just cleared the codes and didn't check you could be overlooking the very problem. If they are good then yes I'd definitely be looking over all your wires.

 

Honestly, I find it unlikely that both of them went bad at the same time, and the codes are for the heater circuit so I'm banking on the fact that bad heaters in the O2 sensors won't make the engine run as poorly as it does.

I'm beginning to lean more towards a faulty PCM. Watching the cam retard on my scanner while it is running...it never moves. As far as I know the PCM controls the advance, and it acts like the timing is not being changed when you step into the accelerator.

Any other ideas? I hate taking a chance on a new PCM and not having it be the problem.

 

Travis

[gmtech4]

i would try and stay away from replacing the PCM,

 

id be looking at those 02 sensors like buddy said

 

get better info to diagnose it or skid the truck out the door,if you call a PCM and its not the problem,you are in big poo poo

[Duelin]

Have you checked your fuses?

[twavor]

Alright, what if I just unplug the O2 sensors for now and try it. If it doesn't act any different, then I'd doubt the O2 sensors are causing the problem, even if they are faulty. As I said, the codes are just for the o2 sensor heater circuit.

The only way that I know to diagnose a faulty PCM is to eliminate everything else...that's what I'm trying to do. This thing acts worse cold it seems. Today I was messing with it and if you hold the brake, put it in low 1 and slowly press the accelerator to the floor, it will run seem to run pretty good, but still seems to lack power. If you just flat out nail the accelerator to the floor like your coming off the line, it will cough, bang, backfire, spit and maybe come out if it in a couple of seconds, although when it's cold it will carry on for several seconds.

So far no codes have came back today, fuel pressure is good, air filter is clean, and I've soaked down the plug wires with soapy water to see if it would make it miss...that didn't make a difference either.

 

Travis

[gmtech4]

you are a tech at a shop ? what about following the diagnoses for the GD codes? do you have any service information available to you ?????

[twavor]

you are a tech at a shop ? what about following the diagnoses for the GD codes? do you have any service information available to you ?????

 

Yes, I'm a tech. I work mostly on ag equipment, but do work on plenty of vehicles, just don't have enough of these kinds of problems to justify Alldata or buying every service manual.

I know enough to know that the heater circuit in an o2 sensor isn't going to cause this problem, though. Now, do you have any more helpful information that I can use? Thanks.

 

Travis

[gmtech4]

nope,good luck travis

[00Silverado4x4]

So taking a few to pull out & inspect o2 sensors isn't worth your time? Especially when your getting codes telling you an area to check. Considering today's technologies going into these vehicles. It ALL has to do with how your truck runs or doesn't in your case. I'd think you'd want to eliminate any & all possibilities.

[gmtech4]

i aquired some info for ya

 

 

DTC P0135 HO2S Heater Performance Bank 1 Sensor 1

Table 1:DTC P0135 – HO2S Heater Circuit Sensor 1

HO2S Bank 1 Sensor 1

Circuit Description

 

Important: If the voltage is measured with a 10?Megaohm Digital Voltmeter, the voltage may read as low as 0.32?volt (320?mV).

The VCM supplies a voltage of approximately 0.45?volt (450?mV) between the HO2S High and HO2S Low circuits. The Heated Oxygen Sensor (HO2S) varies the voltage from approximately 1.0?volt (1000?mV) during rich conditions to 0.10?volt (100?mV) during lean conditions.

When the HO2S temperature measures below 360°C (600°F) the sensor will not produce any voltage and will behave like an open circuit. This will result in an Open Loop operation.

The HO2S heater provides for a faster sensor warm-up which allows the sensor to become active in a shorter period of time. The sensor will remain active during a long extended idle. The DTC P0135 determines if the HO2S is functioning properly by checking the response time of the sensor. This is a type B DTC.

Conditions for Setting the DTC

 

 

Important: If the voltage remains outside of this window for four consecutive seconds, the test is void for this cold start

 

 

 

• The system voltage is greater than 9.0?volts but less than 17.0?volts

 

 

 

• The MAF is less than 27?grams per second

 

 

 

• The engine run time is greater than 2?seconds

 

 

 

• The ECT sensor is less than 32°C

 

 

 

The IAT is less than 32°C

 

 

 

• The deference between the ECT and IAT is no more than 5°C

 

Action Taken When the DTC Sets

 

The VCM turns the malfunction indicator lamp (MIL) ON after 2 consecutive test failures.

Conditions for Clearing the MIL or DTC

 

 

• The control module turns OFF the MIL after 3?consecutive drive trips when the test has run and passed.

 

 

 

• A history DTC will clear if no fault conditions have been detected for 40?warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C?(40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C?(158°F) during the same ignition cycle.

 

 

 

• Use a scan tool in order to clear the DTCs.

 

Diagnostic Aids

 

Important: Never solder the HO2S wires. For proper wire and connection repairs, refer to Wiring Repairs in Engine Electrical.

 

• Check for a poor connection or a damaged harness.

 

 

 

• Inspect the harness for the following conditions:

 

 

 

 

- Backed out terminals

 

 

 

 

- Improper mating

 

 

 

 

- Broken locks

 

 

 

 

- Improperly formed or damaged terminals

 

 

 

 

- A poor terminal to wire connection

 

 

 

 

- A damaged harness

 

Test Description

 

The number(s) below refer to the step number(s) on the Diagnostic Table.

2 The HO2S should be allowed to cool before performing this test. If the HO2S heater is functioning, the signal voltage will gradually increase or decrease as the sensor element warms. If the heater is not functioning, the HO2S signal will remain near the 450mv bias voltage.

 

4 This step determines if the ignition feed circuit to the HO2S is not open or shorted. The test light should be connected to a known good chassis ground, in case the HO2S low or HO2S heater ground circuit is faulty.

 

5 This step checks the HO2S heater ground circuit.

 

6 This step checks for an open or shorted HO2S heater element. The heater element resistance will vary according to HO2S temperature (a hot HO2S heater element will measure a much higher resistance than a HO2S heater element at room temperature). It is important to allow the HO2S to cool before measuring the HO2S heater element resistance.

 

10 This step checks for an open HO2S signal or low circuit which can cause the HO2S heater to appear not to be operating correctly. It is important to check these circuits before replacing the sensor.

 

 

 

Step

 

 

Action

 

 

Value(s)

 

 

Yes

 

 

No

 

 

 

1

 

 

 

 

 

Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and the Failure Records for reference. This data will be lost when the Clear DTC Information function is used. Was the Powertrain On–Board Diagnostic (OBD) System Check performed?

 

 

 

 

—

 

 

 

 

Go to Step 2

 

 

 

 

Go to the Powertrain On Board Diagnostic (OBD) System Check

 

 

 

 

2

 

 

 

 

 

Important: If engine has just been operating, allow the engine to cool for about one half hour before proceeding. 1. Install the scan tool.

2. Turn ON the ignition leaving the engine OFF.

3. Moniter the H02S voltage using the scan tool.

 

Does the H02S voltage displayed gradually decrease by the specified value?

 

 

 

 

0.150V

 

(150 mV)

 

 

 

 

Go to Diagnostic Aids

 

 

 

 

Go to Step 3

 

 

 

 

3

 

 

 

 

Inspect the fuse for the HO2S ignition feed.

 

Is the fuse open?

 

 

 

 

—

 

 

 

 

Go to Step 12

 

 

 

 

Go to Step 4

 

 

 

 

4

 

 

 

 

1. Turn OFF the ignition switch.

2. Disconnect the HO2S electrical connector.

3. Use a test light connected to a known good ground (Do not use HO2S heater ground or HO2S low) in order to probe the ignition feed circuit at the HO2S electrical connector (VCM harness side).

 

Is the test light ON?

 

 

 

 

—

 

 

 

 

Go to Step 5

 

 

 

 

Go to Step 7

 

 

 

 

5

 

 

 

 

Use a test light in order to connect the HO2S ignition feed and the HO2S heater ground.

 

Is the test light ON?

 

 

 

 

—

 

 

 

 

Go to Step 6

 

 

 

 

Go to Step 8

 

 

 

 

6

 

 

 

 

1. Allow the HO2S to cool for at least 10 minutes.

2. Use the J 39200 digital voltmeter (DVM) in order to measure the resistance between the HO2S ignition feed and HO2S heater ground at the HO2S pigtail.

 

Is the HO2S heater resistance within the specified values?

 

 

 

 

3–10 ohms

 

 

 

 

Go to Step 9

 

 

 

 

Go to Step 11

 

 

 

 

7

 

 

 

 

Repair the open in the HO2S ignition feed circuit. Refer to Wiring Repairs in Repair Instructions.

 

Is the action complete?

 

 

 

 

—

 

 

 

 

Go to Step 14

 

 

 

 

—

 

 

 

 

8

 

 

 

 

Repair the open in the HO2S heater ground circuit. Refer to Wiring Repairs in Repair Instructions.

 

Is the action complete?

 

 

 

 

—

 

 

 

 

Go to Step 14

 

 

 

 

—

 

 

 

 

9

 

 

 

 

1. Check for a poor connection at the HO2S harness terminals.

2. If a poor connection is found, replace the terminals. Refer to Wiring Repairs in Repair Instructions.

 

Was a poor connection found?

 

 

 

 

—

 

 

 

 

Go to Step 14

 

 

 

 

Go to Step 10

 

 

 

 

<a href="http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=65772&cellId=28074&pubObjSyskey=2987142&from=sm&pubCellSyskey=2050996&deliveryEffectiveDate=Dec+1%2C+2011#td10">10

 

 

 

 

1. Turn OFF the ignition switch.

2. Disconnect the VCM.

3. Use the J 39200 digital voltmeter (DMM) in order to check the resistance of the H02S signal and H02S low circuit.

 

Is the H02S resistance above the specified value?

 

 

 

 

5 ohms

 

 

 

 

Go to Step 13

 

 

 

 

Go to Step 11

 

 

 

 

11

 

 

 

 

Replace the HO2S. Refer to Heated Oxygen Sensor Replacement .

 

Is the action complete?

 

 

 

 

—

 

 

 

 

Go to Step 14

 

 

 

 

—

 

 

 

 

12

 

 

 

 

1. Check for a short to ground in the battery feed circuit and repair if necessary. Refer to Wiring Repairs in Repair Instructions.

2. Replace the open fuse.

 

Is action complete?

 

 

 

 

—

 

 

 

 

Go to Step 14

 

 

 

 

—

 

 

 

 

13

 

 

 

 

Repair the open or poor connection in the H02S signal or H02S low circuit. Refer to Wiring Repairs in Repair Instructions.

 

Is the action complete?

 

 

 

 

—

 

 

 

 

Go to Step 14

 

 

 

 

—

 

 

 

 

14

 

 

 

 

 

Important: If the engine has just been operating, allow the engine to cool for about one half hour before proceeding. 1. Turn ON the ignition leaving the engine OFF.

2. Use the scan tool in order to select the DTC and the Clear DTC Information functions.

3. Moniter the H02S voltage using the scan tool.

 

Does the H02S voltage displayed gradually decrease by the specified value?

 

 

 

 

0.150V

 

150mV

 

 

 

 

Go to Step 15

 

 

 

 

Go to Step 3

 

 

 

 

15

 

 

 

 

Use the scan tool in order to display the Capture Info and the Review Capture Info function.

 

Are there any DTCs displayed that have not been diagnosed?

 

 

 

 

—